Comparative Studies of the - UQ eSpace - University of Queensland

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Comparative Studies of the \~A...vr.u.ili 

and Internal Anat0111Y of Three 

Species of Caddis Flies (Trichoptera) 

BY 

KATHERINE KORBOOT 

DEPARTMENT OF ENTOMOLOGY 

Volume ]1 

1964 

Number 1

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Comparative Studies of the External 

and Internal Anatomy of Three 

Species of Caddis Flies (Triclloptera) 

by 

KATHERINE I(ORBOOT 

Price: Six Shillings 

University of Queensland Papers 

Department of Entomology 

Volume JI Number 1 

'THE UNIVERSITY OF QUEE"NSLAN-D PRESS 

St. l.1ucia 

7 February 1964

WHOLLY SET UP AND J>RINTED IN AUSTRALIA BY 

WATSON, FERGLJSON AND COMJ>ANY, BRISBANE t QUEENSLAND 

J964 

REGISTERED IN AUSTRALIA FOR TRANSMISSION BY POST AS A nOOK

COMPARATIVE STUDIES OF THE. EXTERNAL 

AND INTE.RNAL ANATOMY OF THREE 

SPECIE.S OF CADDIS FLIES 

(TRICHOPTERA) 

A conlparison is made of the external anatomy of the larva, pupa, and adult, and of the 

internal anatonlY of the larva and adult of Chelunatopsyche modica (McLachlan) (Hydropsychidae), 

Tripleetides volda (Mosely) (Leptoceridae) and Anisoeentropus latifascia (Walker) 

(Calamoceratidae). Special reference is given to the head, ITIouthparts, digestive system, 

nervous system, reproductive systen1, and larval glands. 

'IRE EXTERNAL ANATOMY OF TlIE LARVAE 

Method of Study 

'fhe larvae were fixed in Carnoy's ·fixative and preserved in 70 per cent alcohol. 

rrhey were not renloved from their cases until ready for study, when they were dropped 

into boiling caustic potash solution to clear and soften. The heads were removed and 

studied separately. 

Two types of larvae are recognized in the Trichoptera~ the calTIpodeiforlTI and 

eruciform, with the following chief characteristics: 

Campodeiform 

Eruciform 

Head prognathous 

IIead hypognathous 

Mouth directed forward 

Mouth directed ventrad 

Body depressed 

Body cylindrical 

Legs long, generally all about the san1e Front legs much shorter than the 

length 

others 

Abdo.minal sCgInents sharply 

Abdominal seglnents faintly indicated 

constricted 

Prolegs long, slender, and lTIovable Prolegs short, thick, and fixed

4 KATHERINE KORBOOT 

I...Iateral line wanting 

Lateral line generally present 

Prosternal horn wanting 

Prosternal horn sOlnetimes present 

AbdoIninal tubercles wanting 

Abdominal tubercles present 

Rectal blood gills generally present Rectal blood gills wanting 

Free living or net builders 

Builders of portable cases. 

The larva of Cheumatopsyche modica (McLachlan) (Hydropsychidae) is of the 

campodeiform type but is unusual in that the abdomen is cylindrical. The larvae of 

~rriplectides volda (Mosely) (Leptoceridae) and Anisocentropus latifascia (Walker) 

(Calamoceratidae) are of the eruciform type) but A. latifascia is extremely depressed, 

and neither species bears the prosternal horn. 

L,ong, stout bristles arise fron1 the head, thoracic nota, legs, and anal segments. 

'They are dark in colour with a ]ight~coloured ring at the base, which according to 

I-lickin (1946) is probably a thinning of the membrane, allowing the bristle to 

articulate. 1'he bristles are the" Borsten" of Siltala (.1906), and the thick spines which 

are a characteristic feature of the ventral edge of the fenlur and tibia are the "Sporne" 

of Siltala. 

[-lead 

A,verage .Dimensions of Head of Last lnstar .Larvae: 

Length Breadth 

C. modica 1.6 mm. 1.4 :tnm. 

1'. volda J.5 mn1. ] .0 mIn. 

A. latif'ascia J.5 111m. 0.7 mIn. 

Colour of'the Iiead: ]n C. modica the dorsal surface of the head is dark brown, 

and the ventral surface is a lighter brown. A light band encircles the posterior ventral 

part of the head. In .7'. volda the dorsal surface is dark brown except for a pale frontoclypeus, 

area round the eyes, and various small light patches. l~he ventral surface is a 

light brown and again bears various small light patches. In A. laq'(ascia the dorsal 

surface is dark brown except for the characteristic small Jight patches and a light 

fronto~clypeus. VentraHy the head is dark except for three small pale areas on either 

side of the nlidline. I-lickin (1946) states that the attach,ment of the head muscles to 

the head sclerites is the cause of the characteristic small, elliptical light-coloured 

111arks. 

111e head capsule of trichopterous larvae is heavily sc1erotized, in the shape of a 

truncated cone with two large openings, the occipital foramen and the oral foramen. 

The head capsule is composed of three main sclerites: fronto-clypeus, vertex, and gula. 

Fronto ...clypeus: "This shield-shaped sclerite presents a fascinating study in its 

variation, for here Nature has escutcheoned the genealogy of the order"-Krafka 

(1923). 'The fronto..clypeus js a 1~at plate, bounded laterally by the arms of the 

epicranial suture; to its anterior 111argin is attached the membranous ante-clypeus. 

The epipharynx is fleshy, arises from the undersurface of the labrunl, and projects 

behind the ante-clypeus. Orcutt (1934) and IJoyd (1921) refer to the fronto-clypeus 

as the frons, but, as Hickin (1946) following Snodgrass (1935) points out, the frons 

has the m uscles of the labrunl attached, and so far the presence of this lTIusculature 

in trichopterous larvae has not been made out. Du Porte (1957) refers to the area 

apical to the anterior tentorial pits as the clypeal region and that dorsal to the pits 

as the frontal region. There is some confusion and difference of opinion on the 

homologies of certain regions of the head and mouthparts that are of taxononlic 

importance. M acf)onald (l950) discusses these d ifferen,ces of opinion in S0111e detail. 

'}'he siInp1est type found anl0ng the three larvae stlld ied is that of C. modica. 

~rhe lateraJ 111argins are fOl"lned by the epicranial ar111S, which at first diverge widely 

and converge only slightly to lTICet the ante-clypeus. In T. volda and A. latifascia,

THREE. SPECIES OF CADDIS FLIES (TRICHOPTERA) 5 

the fronto-clypeus differs from this in bearing indentations of the lateral margins in 

association with the anterior tentorial arms. In Cf. modica, as in other .Hydropsychidae, 

the anterior tentorial pits are removed from the epicranial arms. According to Krafka 

the anterior tentorial pits have retained their original position on the head, and the 

epicranial arms have moved out and away from them, due to the tendency to broaden 

the head. 

Vertex: The vertex forlns the greater part of the head capsule, extending laterad 

and ventrad to form the lateral and the greater part of the ventral aspect of the head. 

The area which Thave called here the vertex has been referred to by some authors as 

the epicranial sclerite, and by others as the gena. rrhe region of the vertex which bears 

the eyes and antennae could be referred to as the genal region, being demarcated by 

a line drawn froln the anterior tentorial pits to the eyes. 

Eyes. In nlost trichopterous larvae the eyes consist of six sinlple, closely 

adjacent~ lateral ocelli. They are always black in colour and are usually surrounded 

by an area where piglnentation of the cuticle is absent. The eyes are slightly elevated, 

and their position on the vertex varies fron1 a point near the antero-lateral lnargins 

of the head to a point as far caudad as the separation of the epicranial arms. There is 

only slight variation in the position of the eyes on the vertex in the three species 

studied. They are situated furthest anteriorly in T. volda. The larvae appear to use the 

eyes only in differentiation of light and dark; the food is met accidentally by the fore 

legs and passed to the nl0uth, where it is accepted or rejected. 

Antennae. The antennae are s111aIJ, simple, and easily overlooked. Siltala 

(1906) recognizes two types: one with two distal pieces, the other with only one distal 

piece. Their position varies with the eyes, from imInediately behind the rnandibles 

to a point far up on the head. The first type of Siltala's has a basal segment upon 

which are nlounted two so-called palps and numerous sensory setae. The second type 

has a single palp. T'he first type is stated to be common in the campodeiform group, 

while the second is peculiar to the eruciform group. 

I have found no trace of antennae in C. modica. The antennae of T. volda and 

A. lat~rascia have a similar position near the base of the mandibles. A. lat~fascia has 

a. long slender "palp" set on a raised base while in T. volda the "palp" is reduced in 

SIze. 

Gula: Siltala (1906) has pointed out that the gular sclcrite is not strictly homologous 

throughout the order. In SOlTI.e cases Siltala considers this sclerite to be the 

mentum and in others the true submentum. Das (1937) is also of the opinion that a 

true gular sclerite is totally absent in trichopterous larvae, the so-called gular sclerite 

being the submentuln. I-lickin points out that the modifications of the gular sclerites 

aInongst the fanlilles of 1~richoptera are closely associated with the feeding habits of 

the larvae. . 

1 have followed I(rafka (l923) in applying the terTll "open" to a gula which 

reaches the occipital forarnen and "closed" where, the two parts of the vertex are 

contiguous, preventing the gula fronl reaching the occipital forarnen. T. volda shows 

a great deve]oplnent of the open type; the gula is a broad plate widely separating the 

vertex. .l n A. latifascia the gula is of the closed type, being a small triangular sclerite 

at the proximal end of the labium. C. 1nodica has a closed gula which is irregularly 

pentagonal. At the base of the gular suture is a nlinute area which represents a 

vestige of the posterior piece found in other Hydropsychids. 

Chaetotaxy: ~rhe chaetotaxy of the head has been worked out by 'Uhner (1909). 

According to this author, the clypeus (here referred to as the fronto-c1ypeus) bears 

typically thirteen bristles of which seven are situated on the anterior TIlargin, one of 

these being in the lniddle and three associated with each lateral angle; of the 

relnainder, three bristles are situated near each lateral lnargin, one being aborally 

placed and two oraliy placed.


In C. modica the bristle arrangement is obscured by the presence of a large 

number of secondary bristles. The number of prilnary bristles differs from that 

proposed by Ulmer by diIninutioll of the bristles along the anterior margin, there 

being one central and two lateral on each side. On the vertex three stout bristles occur 

in front of each eye and three behind. In T. volda six bristles occur on the anterior 

margin of the fronto-clypeus, three associated with each lateral angle, and three occur 

on each side associated with the lateral nlargin. On the vertex a stout bristle occurs 

in front of each eye and another behind the eye. In A. latifascia the fronto-clypeus 

bears four bristles. The seven bristles of the anterior margin which are nlentioned by 

Uhner are absent. l'here are two lateral bristles on either side, one aboral and one 

oral. There are six pairs of bristles on the vertex., one large oral bristle on either side, 

one on the inner side of the eye, one above the eye, and three posterior bristles in a 

row. 

,Endoskeleton: The endoskeleton of the head is greatly reduced. ~rhe tentorium 

consists of an extrelnely slender, fibre-like bridge, and flexible, fIbre-like anterior and 

posterior arms extending through the head frOln the dorsal to the ventral walL The 

anterior arms arise about half way along the epicranial arms in 1". volda and 

A. latijascia, but in C. modica they arise a short distance nlesad of the epicranial 

arms. 1'he posterior invaginations are located in the angles for.med by the gula and the 

vertex in T. volda, and near the caudal ends of the gular suture in A. lat1fascia and 

C. modica. 

!vlouthparts: The 11louthparts of trichopterous larvae are well developed and of 

the nlandibulate type. The Inandibles are always heavily sclerotized and well adapted 

for gripping and tearing. The articulations are of the acetabulum-condyle type. 

The dorsal articulation has the acetabulunl on the nlandible and the condyle on the 

vertex, while in the ventral one the conditions are reversed. The labrum is separated 

from the fronto-clypeus by the ante-clypeus, which forms a hinge allowing the 

labrum to fold back within the capsule of the head. 

1'he labium and maxillae are united to for.m the underlip. The labiunl has its 

basal attachment on the anterior Inargin of the gula. It is cone-like in shape, with a 

broad basal section representing the postmentunl, and terlllinating in a segment 

which represents the prenlentum. l"'his segnlent bears a pair of one- or two-segmented 

labial paJps, or the palps are absent. l'he dorsal surface of the prementum. probably 

represents the hypopharynx. The cOlnbined structure nlay be called the prelnentohypopharyngeallobe, 

as has been done by Snodgrass (1935). 

The cardo of the Inaxilla is attached to the postlnentunl of the labium on each 

side. The stipes is not capable of independcntmovelnent but moves with the labium. 

The cardo and stipes are broad structures bearing many slnall hairs. Lying close to 

the maxillary palp, which is four- or five-segmented, is the inner lobe or galea. 

In C. modica the labrum is sclerotized, brown in colour, with pale selnicircular 

areas posteriorly, and provided with dense lateral brushes of long hairs and two long 

anterior bristles. The labrum of T. volda is lightly sclerotized, except for two heavily 

scl erotized areas at the posterior angles. A sn1all median anterior incision is present, 

and the outer angles of the anterior D1argin are provided with a dense group of short 

hairs. In A. lat~lascia the labrunl is slightly sclerotized and sub-rectanguiar. Again 

the llledian anterior incision is shallow, and dense brushes of fine bristles are borne 

on the anterior lateral angles. rren stout bristles on either side project anteriorly 

from the upper surface. 

In C. modica th.e 111andibles are amber coloured and sylnmetricaL rrhe cutting 

edge is along the inner Inargin, and six sharp teeth are borne apically. Two bristles 

are present on the outer edge of each mandible, and a brush of slnaJl hairs on the inner 

edge. In 1~. volda the mandibles are asymmetrical and black in colour. Apically the 

left bears two sharp teeth, and the right four blunt teeth. Again two bristles are present

THREE SPECIES OF CADDIS FLIES (TRICHOPTERA) 7 

on the outer edge of each mandible. The mandibles ofA. lat~[ascia are symlnetrical 

in shape, but asymmetrically pigmented, the dark irregular pattern occupying different 

areas on each. There are three stout, blunt, apical teeth and a dense brush of fine, 

yellow hairs on the inner margin. 

In T. volda the maxillary lobe and palp are densely haired, the palp being fivesegmented. 

In the three genera the lobe is shorter than the palp. In C. modica the 

palp is four-segmented with two warty knobs at the tip, while the palp of A. latifascia 

is four-segmented with papillae at the tip. In C. modica the ligula is a distal beak-like 

projection of the labium bearing the opening of the spinning gland. In T. volda and 

A. latifascia there is no such projection. Hickin considers this distal region between 

the palps as probably being the fused glossae and paraglossae. J-,abial palps are 

minute in the three species. No division of the postmentum into Inentun1 and 

sublnentum is evident. 

1norax 

The thorax consists of three distinct leg-bearing seglnents. The pronotum is a 

heavily sclerotized plate which extends over the sides of the prothorax. The anterior 

n1argin of the prothorax of 1-'. volda bears a number of stout forwardly projecting 

serrations, and the posterior margin of the pronotum of C:. modica bears a nurnber of 

backwardly projecting serrations. In C. modica the lneso- and Inetanota are well 

sclerotized. In T. volda the mesonotu:m is well sclerotized, but rnarked with pale, 

weakly sclerotized patches, and the metanotuln consists of four slnall, isolated 

sclerotized plates. In A. 1atffascia the mesonotum bears a slightly sclerotized central 

shield, and the n1etanotu'm is entirely n1en1branous. 

On the sides of the three thoracic seglnents are sclerotized plates which represent 

the episternum and epimeron. In the propleural region of C. modica the episternum 

and epimeron are distinct plates. The episterna and epin1era of the lneso- and metapleura 

are dark, narrow, band-like sclerites which give support to the bases of the 

coxae. In T. volda and A. latifascia the pleural sclerites are large and plate-like, with 

distinct pleural sutures. In an three species the propleurae bear a trochantin, one edge 

of which is free and projecting, appearing as a scraper. The posterior edge articulates 

with the episternum by a membranous connection. In A. lati;[ascia the outer edge of 

the trochantin is finely serratedft 

Long and short bristles are arranged in characteristic positions on the thoracic 

nota. In C. modica the nota are covered with fine secondary hristles. 'The pronotum has 

a stout antero..lateral bristle on each side and also a posterior bristle on either side of 

the midline. The meso- and rnetanota have the posterior-median bristles. In T. volda 

the pronotum has a lateral fringe of long, fine bristles, and the other thoracic nota 

are bare of bristles. The thoracic nota of A. latifascia are well supplied with bristles. 

'The pronotum bears ten bristles along the anterior margin, three bristles along each 

lateral-anterior margin, and two lateral, two submedian, and two dorso-lateral 

bristles. I'he mesonotum bears eight anterior bristles and, on each side, three anterolateral 

and four dorsal. 'The metanotum bears on each side four antero-lateral, one 

mid-dorsal, and four dorso-Iateral bristles. 

Legs: 'Trichopterous larvae have three pairs of well-developed jointed legs. 

'The coxa is large and entirely sclerotized. An incision on the dorsal surface of the 

distal lnargin is covered with a thin lnembrane and allows the short triangular trochanter 

to move in an upward direction. I'he femur is broad and flattened, usually with 

a series of spines along the ventral edge. The felnur is inserted deeply into the distal 

end of the trochanter, with a strong men1branous sheath forming a hinge between 

the seglnents. The tibia is undivided, except in SOlne Leptocerids. The tarsus is 

undivided, with a large claw armed with a basal tooth.


In C. modica the three pairs of thoracic legs do not differ greatly in size. The tibia 

and tarsus are covered with short hairs which, according to Lestage (1921), serve in 

Hydropsyche sp. as a brush for cleaning the nets. The ventral surface of the femur 

bears numerous slnall spines. In T. volda the legs are long and thin, with dark, annular 

patches on all segments. The middle and hind legs have a peculiar jointing. 'The trochanter 

is unusually long, and the femur slightly shorter. The tibia appears to be twosegmented, 

and the tarsus is long. The ventral surface of each felnur has a few small 

spines. In A. latifascia the front and mid legs are short and stout, the hind legs long 

and slender. I'he front legs bear a heavily pigmented band on the tibia and a light 

band on the tarsus. I'he Inid legs have heavy bands on the femur and tibia and a light 

band on the tarsus. The hind legs bear two bands on the elongate tibia and single 

bands on the femur and tarsus. The ventral surface of each femur is free of spines. 

Abdom.en 

1'he abdonlen is nine-seg,m.ented and ahnost entirely membranous. In C. modica 

the abdomen is slightly sclerotized dorsally, and the eighth and ninth seglnents each 

have two snlall ventral, sclerotized plates, which are fringed posteriorly with bristles. 

The ninth seglnent also has two small lateral plates on either side. The abdomen is 

widest at the second and third segments. In life, the colour is pale green. 'The tubercles 

and lateral line are absent, and the intersegmental grooves are slight. In T. volda 

the abdomen is light grey, the intersegmental grooves are shallow, and the abdominal 

tubercles are well developed. 'The dorsal tubercles are fleshy, non-sclerotized, and 

lobe-like, and bear two fine bristles. The lateral tubercles are two small sclerotized 

protuberances, each bearing a single bristle. The lateral line extends fronl the anterior 

margin of segment three to the posterior margin of segtnent seven. rn A. latifascia 

the abdomen is creamish-yellow and entirely menlbranous, except for a slight sclerotization 

at the hind margin of the first abdolninal seglncnt. The abdomen is extrenlely 

flattened dorso-ventrally, and has a laterally scalloped appearance as the intersegJuental 

areas are narrower than the segmental areas. The intersegmental grooves are 

distinct. The tubercles on the first abdolninal seglnent are not very pronounced, 

being slight, flattened swellings. The lateral line extends fronl the anterior margin of 

segment three to the posterior Inargin of segment seven. The hairs of the lateral line 

are very long and appear as a lateral fringe. The abdominal tubercles serve to keep a 

space between the insect and its case for the free circulation of the respiratory currents 

of water. The lateral line also keeps a continuous flow of water through the case. 

Gills: The acquatic habit of trichopterous larvae has led to a closed tracheal 

system and, in most, to gill development. A large proportion of oxygen absorption 

however is cuticular. The gills are filam,entous and may arise in tufts or singly. When 

present they arise only at certain definite places on the body. There are three longitudinal 

rows on each side of the abdomen: 

(I) A lateral series which is located near the mid-lateral surface of the body. 

(2) A subdorsal series, which is located above the lateral series, just below the 

dorsal surface of the body. 

(3) A subventral series, which is located below the lateral series, just above the 

ventral surface of the body. 

Gill pattern. In C. lnodica pale pink, branched tracheal gills are present on the 

lneso- and .metathorax and abdominal seglnents one to eight. "-fhe gills are approxill1ately 

two-thirds of tlle length of the segment which bears them. Mesothorax--· 

ten branched subventral series. Metathorax-,---ten branched mid-subventral series, and 

t.en branched posterior-subventral series. Abdominal segments one, two, three, four 

-ten branched lateral and subventral series. Abdominal segments five, six, seven, 

eight-two branched subventral series. In T. volda the tracheal gills are long, white, 

unbranched, finger-like, and taper slightly at the distal end. In a fresh specinlen


they are equal to the length of the segment which bears thenl, but on preservation they 

shrink. The gills are borne on the cephalic end of abdominal segments one to eight 

inclusive. Abdominal segment one-unbranched lateral, subdorsal, and subventral 

series. Abdominal segments two to eight--unbranched subventral and subdorsal 

series. In A. tatlfascia, as in .T. volda, unbranched, long, white, finger-like tracheal 

gills, which taper distally, and which are equal in length to the seglnent which bears 

them, are present on the abdolnen. Abdom-inal segment two---unbranched lateral 

series of three pairs, subdorsal series of three pairs, and subventral series of three 

pairs. Abdolninal segments three to eight--unbranched subdorsal series of three 

p",irs and subventral series of three pairs. 

Besides the external tracheal gills, C. nlodica possesses four white., transparent 

anal gills projecting from the T-shaped anus. The gills are in direct communication 

with the body cavity, and when retracted they lie in the rectuln, of which they are 

outgrowths. When the larva is in need of extra oxygen, blood passes from the blood 

sinuses into the gins, and the resulting pressure extrudes the gills through the anus 

to the exterior, where gaseous exchange takes place through the wall of the gil1. At 

rest the width of the gill is about one-third of its length, which is nonnally slightly 

less than the width of the ninth segment. The gill is capable of extrusion to about 

three times its retracted length. 

Abdominal undulatory movements have been observed in C. moc/iea and 

A. lat~fascia. ~rhe abdomen is moved rhythmically in the vertical plane, causing a flow 

of water over the gills and the surface of the body, thus aiding in respiration. These 

rhythm-ic undulatory movements were also noted in the prepupal stages. 

The ninth abdominal segnlent bears a pair of fleshy appendages or pygopods, 

each of which terminates in a movable chitinous hook. In C. modica the appendages 

are long and slender, and the claws are strong and serve to grip the silken net when 

the larva is running backwards. 1'he two appendages lie close together and are well 

armed with stout bristles, a dense brush of bristles being prese'nt at the base of the 

claws. ]n T. volda the anal appendages are nl0re sq uat and the claw is shorter. The 

two appendages are well separated and covered with an irregular pattern of long 

bristles. The anus is slit-like. The anal appendages of A. lati;fascia are small and squat. 

1'he claw is double and the bristles sparse. Three long bristles occur near the apex. 

The appendages he far apart and the anus is slit-like. Tn 1'. volda and A. latifascia 

the claws are used to grip the silken lining of the case. 

NOTE 

Two larvae of Anisocentropus elegans Walker were found in the habitat of 

A. lat~fascia and in sim.ilar cases made of leaves. One specimen was killed for 

exanlination of the larva, and the other was bred to the adult. 

Features in which A. elegans larva differs from A. lat(fascia: 

Seven bristles are situated on the anterior marg-in of the fronto-clypeus arranged 

in the way described by lJlmer. Four small bristles are associated with each]ateral 

margin. The labrunl is lightly sclerotized and globular. 1'he median anterior incision 

is shallow, and dense brushes of fine hairs are present on the anterior lateral angles. 

Two stout bristles project from the upper surface. The m.andibles are dark brown and 

symlnetrical, each bearing two stout, blunt apical teeth. 

The pronotunl has three lateral and five anterior bristles on either side. The nlesonotuln 

has three antero-lateral and three Inedian pairs, and the metanotum three 

anterior and two posterior median pairs. The lneso- and metanota are completely 

membranous. The legs are short and stout, and there is slight variation in size from 

the fore to the hind legs, the fore being the stoutest and shortest. 

The abdonlen is entirely melnbranous. It is 110t flattened dorsoventrally, but is in 

the form of a hairless cylinder. The lateral margins of the abdomen lack the scalloped


appearance of A. latifascia. The hairs of the lateral line are short, and the lateral line 

extends from the anterior margin of segment two to the posterior margin of segment 

seven. Gills are lacking. 

It is interesting to note that on one occasion a male of A. elegans and a fenlale of 

A. latifascia were taken in copula at the light trap in September at Enoggera Creek, 

Brisbane. The female was kept alive in the breeding cage, and on the second day of 

captivity a cream coloured spherical egg mass was observed protruding from her 

abdomen. On her third day of captivity the fenlale dropped the nlass into the water 

of the cage. The mucilage covering of the mass swelled to double its original size but 

the eggs, which were arranged in a spiral fashion in the mass, failed to develop, the 

whole mass finally disintegrating in the water. 

THE INTERNAL ANATOMY OF THE LARVAE 

M-ethod of Study 

H. E. :Branch (1922) was followed to advantage in using hot water killing for 

spcciInens to be used in gross dissection, but Carnoy's fixative, and not the Gilson's 

fixing solution recomnlended by Branch, was used. The internal anatOlny of the larvae 

was studied from gross dissections, glycerin whole Inounts, and eight to ten I.L 

longitudinal and transverse microtome sections. Where possible larvae fresh froIn 

ecdysis were used for sectioning, elnbedded in 4 per cent cetIoidin and wax. Specilnens 

which had been preserved for some tillle in alcohol became exceedingly hard, and a 

special technique for softening was therefore necessary. The specinlens were soaked 

in diaphanol for twelve hours. 

Digestive System 

In C. modica the buccal cavity is large, occupying more than half of the space of 

the head capsule. ]t leads into a narrow tube, the oesophagus, a slight anterior 

distension of which could represent a very ill-defined pharynx. 1~he oesophagus 

expands slightly in the prothorax, at the posterior end of which it enlarges to form the 

crop. At the posterior lnargin of the mesothorax the fore-gut constricts to about half 

its width and forllls the cylindrical proventriculus. l'his is a hard structure with a 

nUlnber of sclerotized teeth 011 the intinla, large circular muscles, and, outside these, 

six longitudinal muscles arranged in pairs. The proventriculus functions as a grinding 

organ and possibly as a straining device. It occupies the entire metathorax. 

The mid-gut extends from the posterior end of the metathorax to the sixth 

abdonlinal segnlent. It is darker than the rest of the alimentary canal and lacks the 

silvery tone of the fore-gut. The proventriculus pushes into the forward end of the 

mesenteron, forming the stolllodaeal invagination. The mid-gut is about one-third 

as wide as the abdomen and is foJded into transverse ridges which increase the assimilative 

area. The longitudinal muscles break up to form a layer of muscles around the 

tube. Beneath these muscles is a very thin layer of circular muscles. N-o distinct valve 

is present between the mid- and hind-gut, but the latter is of narrower dialneter. 

At the junction of the mid- and hind-gut arises the circle of six Malpighian 

tubules, two dorsal, two lateral, and two ventral. The dorsal tubules extend forward 

through the abdominal cavity into the metathorax. The lateral pair coil forwards, 

lying close to the alinlentary canal as far as the third abdominal segnlent, and then 

pass backwards, lying close to the body wall as far as the eighth abdominal segment. 

T'he ventral pair also coil forwards, passing to the fourth abdolninal seglnent, and 

pass back in a zigzag fashion to the eighth abdonlinal segment. I'he tubules are 

irregular in outline and light yellow to white, with patches of dark pigment. 

The intestine is oval in outline. A constriction at the posterior end of the seventh 

seglnent is the only indication of change from small to 1arge intestine. At the posterior 

end of the eighth segn1ent the intestine is again constricted before the rectulll. At this


point the walls of the intestine are invaginated as folds which posteriorly become 

longer and fewer to forIn the blood gills which lie in the rectum. The rectuIn extends 

through segInent nine; its diaIneter becomes narro\ver after its original swelling, 

following the constriction in segment eight, and then dilates again to accoffiInodate 

the invaginations forIning the blood gins. Jn C. modica the rectunl. thus serves the 

dual function of elinlination of waste m,aterial and of respiration. Glycerin InOlll1ts 

show that the blood gills are not tracheated. 

The anterior part of the intestine has a heavy nlusculature, being surrounded 

by large circular and narro\v longitudinal Inuscles. The .nl usculature of the rectum, 

however, is thin, and the walls are almost transparent. 

In T. volda the oesophagus expands in the mesothorax into a short sac-like crop. 

At the posterior margin of the mesothorax, as in C. modica, the fore-gut constricts 

to form the small proventriculus. The latter is like a posterior dilation of the crop, 

as the heavy muscle coat and sclerotized teeth present in C. modica are lacking. 

T. volda is a herbivorous species, and the grinding teeth of the semi-carnivore are 

not necessary. 

As in C. modica, the mid-gut extends froIn the posterior end of the metathorax 

to the sixth abdominal segnlen~. In the second abdominal segm.ent the l1lid-gut is 

slightly constricted. The six Malpighian tubules have the same arrangernent as in 

C. Inodica but are slightly longer. The dorsal pair coil forwards into the metathorax, 

then turn back to the first abdonlinal seglnent. l'he lateral pair coil forwards to the 

second abdominal seglnent, turn, and pass back to the eighth abdominal segment. 

The ventral pair continue forward to segment three before turning back. 

There is no constriction between small and large intestine, the intestine being a 

wide tube, narrowing at the beginning of segnlent eight before the rectum. 

In A. lat~rascia the oesophagus dilates slightly in the Inesothorax to form the 

crop, wh.ich is marked fron1 the proventriculus at the anterior margin of the meta.. 

thorax by a slight constriction. As in 1". volda, the proventriculus lacks sclerotized 

teeth. 

The mid-gut is shorter than that of C. modica or T. volda~ extending to the fifth 

abd olninal segment. Jt is in the forIn of an extremely depressed sac. 'rl1e six Malpigh.. 

ian tubules are arranged as in C. modica and .T. volda. The dorsal tubules coil forward 

to the second or third segnlent and back to the eighth. l'he lateral tubules follow a 

zigzag path to the nlesothorax, and the ventral pair pass to the first abdominal 

segn1ent and back to the fourth. 

The intestine and rectum resemble those of T. voldo, the rectum. gradually 

narrowing as it nears the anus. 

Circulatory System 

'The dorsal blood vessel extends in tubular form from the middle of the head to 

the middle of the ninth abdominal segnlent. The tip of the cephalic end bifurcates 

to give two short aortic branches. 

The nine pairs of alary Inuscles occupy a ventral intersegmental position, the 

first pair between the metathorax and the first abdonlinal segment, and the last 

between the eighth and ninth abdominal segments. 

Reproductive ..)ystenl 

As pointed out by Branch this system seems to have been given adequate attention 

by Zander (1901), Liibben (1907), and .M:arshall (1907). 1 merely located the 

organs in gross dissection. As to the period of appearance of the organs, there is 

difference of opinion. Klapalek (1889), Vorhies (1905), an d Pictet (1834) state that 

the organs do not appear until near the period of pupation. Ltibben discusses conditions 

in the transforming larva, while ,Marshall speaks of the condition of the organs


in the youngest larva he had, but does not state the stage. 1 have observed the gonads 

to be present in the last three larval instars in C. modica, T. volda, and A. latifascia. 

In over fifty specimens dissected the gonads appear to take two form,s-narrow 

elongate tubes and small oval bodies. The elongate type probably represents the 

future male organs and the oval ones the female organs. The gonads are paired and 

occur in the fourth abdom,inal segment in the three species. F'rom a cOlnpilation of 

records, the position of the gonads in Trichopterous larvae seems to be in either the 

fourth or fifth segment. Each gonad bears two attachments, one a thread-like tissue, 

the other a duct. The former arises from the outer side of the gonad and extends to 

the ventral body wall at the cephalic end of the third abdonlinal segment. The latter 

arises from the inner side oftbe gonad, and the tubules of the gonad converge towards 

the base of the duct. The duct extends posteriorly to the ventral body wall of the eighth 

segn1ent. The ducts of the two sides do not fuse and, in these three species, do not 

appear to pass to the exterior as reported by Ijjbben (1907). 

Nervous System 

The nervous system of trichopterous larvae is generalized~ with three thoracic 

pairs and eight abdolninal pairs of ganglia. 

In ('f. modica the brain is near the front of the head. The optic nerves branch on 

leaving the ganglion. Froln the small frontal ganglion a branched nerve proceeds 

forwards, the outer branch supplying the labrum and the inner branch the dorsal 

region of the buccal cavity. 

An oesophageal ring of the tritocerebrum encircles the oesophagus. 

Of the three pairs of nerves froln the sub-oesophageal ganglion, the Inost dorsal 

extends forwards and upwards and branches in front of the frontal ganglion. One 

branch innervates the base of the labru:m and the other the mandible. 'fhe second 

pair of nerves also branches, the outer branch supplying the lnusculature of the 

maxilla, and the inner dividing again to supply the n1axillary sclerite and the labium. 

T'he third pair of nerves is ventral in position and innervates the labium. 

Each ganglion of the thorax and abdomen represents a fused pair of ganglia. 

A pair of connectives passes from. the sub-oesophageal ganglion to the first thoracic 

gangUon in the prothorax. The pro- and mesothoracic ganglia are of about the same 

size as the sub-oesophageal ganglion and are situated in the lniddle of the segment 

which they innervate. The metathoracic ganglion is larger than those of the preceding 

seglnents~ and is situated at the posterior border of the metathorax and incompletely 

fused with the first abdominal ganglion. 'The ganglia of abdominal segments two and 

three are situated in the posterior halves of segments one and two respectively. 

Abdominal ganglion four is situated in the anterior half of its segment, and abdotninal 

ganglion five in the posterior half of seglnent five. 'fhe sixth, seven th, and eighth 

abdominal ganglia are closely united and lie in the sixth abdominal segment. 

The thoracic ganglia and abdominal ganglia one to six innervate their respective 

segments and appendages. The seventh abdo'minal ganglion bears a single pair of 

fine nerves which extend backward into segnlent seven. The eighth abdolninal ganglion 

innervates segments eight and nine and the anal appendages. 

The ganglia and nerves of the head of T. volda and A. lat~fascia do not differ 

materially from those of C. rnodica. However the three species differ considerably 

as to the relation of the thoracic and abdominal ganglia to their respective segnlents. 

All have three thoracic and eight abdominal ganglia; but in A. latifascia there are 

apparently only seven abdominal ganglia, due to the complete fusion of the first 

abdominal and metathoracic ganglia, the enlarged cOlnposite ganglion occupying a 

central position in the metathorax. In C. modica the first abdolninal ganglion has 

incompletely united with the ganglion of the metathorax and come to lie in the 

posterior half of the nletathorax. In T. volda the first abdominal ganglion is distinctly 

separated from the metathoracic, lying in the middle of its own segnlent.

THREE SPECJES OF CADDIS FLIES (TRICHOPTERA) 13 

In T. volda abdominal ganglia two~ three, [our, five, and six occupy central positions 

in their respective segments, while ganglia seven and eight lie closely united 

as a large central ganglion in segment seven, indicating a forward migration of 

ganglion eight. In A. lat~fascia abdominal ganglion two lies in the first abdominal 

segnlent, segment two being void of a ganglion but being innervated by the nerve 

branches from ganglion two. The ganglia of segnlents three, four, five, and six occur 

in their respective seglnents near the posterior margins. Segment seven is void of a 

ganglion, ganglion seven being closely united, but not fused, with ganglion eight in 

the middle of segment eight. 

Silk Glands 

rrhese are the most prominent glands of the trichopterous larva and have a 

sinlilar structure in the three species studied. They extend fron1 the labial spinneret 

to the sixth abdoTI1inal segnlent and fi.ll that part of the body cavity not occupied by the 

aliluentary canal and fat body. They are twice bent and comprise two regions, the 

glandular part and the duct. The glands lie ventral to the alimentary canal in the thorax 

and lateral to it in the abdolnen. In the sixth abdolninal segment th.ey narrow and lie 

beneath the intestine. 

In the centre of the anterior margin of the labiuln is the spinneret. It is connected 

to a slender tube which divides; the two ducts pass under the nerves supplying 

the nlouthparts and the tentoriulll and, on reaching the sub-oesophageal ganglion, 

run close together beneath the oesophagus and open into the silk glands. (]ose 

behind the spinneret is a muscular silk press which controls the flow of secretion. 

Further details of the structure of the silk press are given by Ciilson (1894). 

TIlE EXTERNAL ANATOMY OF TI-IE PREPUPAE AND PUPAE 

.Method 0.[ Study 

r-rhe information presented was obtained during the rearing of larvae to ad ults. 

·Pupae were fixed for four hours in Carnoy's fixative and preserved in 80 per cent 

alcohol. Pupal skins were dehydrated in alcohol and lllounted in Canada balsam.. 

.Pupal Cocoon 

A cocoon is characteristic of all trichopterous pupae. In ('1. modica the cocoon is 

Inade of small stones cemented together into an oval-roofed chamber. ~rhe floor of 

the cha:mber is a rock or sub·merged log. When the tinle of pupation draws near, the 

Inature larva leaves its silken retreat, wanders to the floor of the stream, collects 

stones of about the sa:me size into a heap, and then begins to construct the pupal 

chanlber. Many specilnens of C. modica were observed in aquaria, and in all cases 

the larvae left their original ho.me and pupated elsewhere. The site chosen for pupation 

may however be near the retreat of another larva. Between the stones forlnhlg the 

pupal chanlber snlall spaces occur, through which water passes to the pupa inside. 

Undulations of the pupal abdolnen keep the water circulating. The pupal cocoon of 

C. n10dica differs fro:m that of the case-bearing larva, where the cocoon is n1ade from 

the larval case by blocking in various ways the front and rear openings, so as to protect 

the pupa from enelnies and silt. In .A. lat~fascia the posterior net is repJaced by a silken 

plug, and anteriorly a silken lid is spun, the Hd having a snlall slit-like opening. The 

pupal gratings lie at the extreme ends of the leaf fraglnent which fornls the floor of 

the pupal shelter. The larval case of T. volda is sealed posteriorly with a silken plug, 

and anteriorly a grating of fine silken threads is spun. The pupal gratings are not 

situated at the extreme ends of the case but lie a short distance within the case. 

Prepupal Period 

When the pupal case is cO.lnpleted changes occur in the larva. As described by 

Hickin, it becomes stiff, the .bead and abdolnen lose their usual flexibility, and the


inter-segmental grooves of the abdomen become very indistinct. The legs occupy 

positions characteristic of the prepupal phase. 

C. lnodica: Fore legs. The coxa and trochanter point downwards and 

forwards, the fenlur points up, and the tibia and tarsus point forwards, at an angle, 

lying on either side of the head. 

Mid legs. T'he coxa and trochanter point down and back, the femur is vertical, 

and the tibia and tarsus lie in a horizontal position on either side of the abdomen. 

Hind legs. As for mid legs. 

T. volda: Fore legs. The coxa and trochanter are directed down and forwards. 

The femur, tibia, and tarsus are directed forwards and upwards. 

Mid legs. :Held in the SalTIe position as the fore legs. 

Hind legs. Coxa and trochanter are directed forwards and upwards. Femur,. 

tibia, and tarsus follow the dorsal surface of the thorax in a forward position. 

A.. latifascia: The fore and mid. legs are pressed close to the sides of the body. 

Fore legs. The coxa and trochanter are directed upward and forward. The 

femur, tibia, and tarsus are pressed close to the sides of the head. 

Mid legs. The coxa, trochanter, and femur are directed upwards and forwards. 

'The tibia and tarsus lie close to the head and are parallel to those of the fore legs. 

Hind legs. The coxa and trochanter are directed posteriorly, femur up and 

back, and the tibia and tarsus follow the abdomen on the dorsal surface. 

Pupa 

All Trichoptera have exarate pupae with functional mandibles (pupae liberae of 

Hickin (1949), decticous pupae of I-linton (1946) ). The pupal integument is colourless 

and loosely envelops the forming iInago lying within. In external appearance the 

pupa has ll1any of the characteristics of the adult. I-Iowever the mandibles and dorsal 

hook-bearing plates provide features of exceptional interest. The dorsal hook-bearing 

plates are a series of horny sclerites used for gripping the sides of the case when the 

pupa is enlerging, and the mandibles are used for cutting through the case at 

em.ergence. 

liead 

The head resembles very closely that of the adult, but the mouthparts ditIer 

greatly. The imago feeds very little, if at all, and when it does feed the nutrient is of a 

Jiquid nature. The pupal mandibles however carry out the important function of 

cutting the exit hole in the pupal case and are well developed. The labrum is very 

different fr01TI that of the larva and adult. The antennae are straight and lic close 

along the sides of the pupa. They possess the same number of segments as the· 

antennae of the imago and are of the same length and shape. In all cases the antennae 

pass in front of the eyes and along the anterior margin of the wing pads. 

In C. modica the antennae end at the ventral aspect of the eighth segment, after 

rolling twice around that segment. In T. volda they extend to the ninth segnlent, 

around which they curl twelve times, the tip of the antenna being tucked down_ 

ventrally. The antennae of A. latifascia lie straight along the sides of the body and 

extend about 5.6 Inm. beyond the tips of the anal appendages. 

In the three species studied the colouration of the pupal eyes followed the samepattern. 

The eyes were colourless in the newly formed pupa, and passed through brown 

and red before reaching the black colour of the mature pupal eye. 

The labrum is armed with stout bristles. In C. modica it is flat and plate-like, and 

lies in the same plane as the fronto-clypeus. A group oflarge bristles is present distally,


and a pair of promixal groups is present on each side. I'he anterior margin bears a 

double indentation. In T. volda the labrum is a flat sub-rectangular plate lying in the 

same plane as the fronto-clypeus. It is covered with long stout bristles and bears a 

slight indentation along the posterior margin, while the anterior margin is slightly 

pointed in the Iniddle. The labrunl of A. latifascia is slnal1~ sub-rectangular, and 

projects outwards from the head. It bears anteriorly a group of stout bristles and 

posteriorly two large bristles. 

The mandibles are long and heavily sclerotized. In C. mo~lica they are sickleshaped 

and have three large and two small apical teeth. At the base are two ventral 

groups each of six stout black bristles. In T. volda the apices of the lnandibles are 

sickle-shaped, and a smalJ tooth is present in the middle. 'Two long bristles are borne 

on the outer margin near the base. In A. lati}ascia the apices are very sharp but have 

no teeth. There are two small bristles on the outer side near the base. 

The maxillary palps are well developed and five-segmented. The labial paIps 

are three segmented. 

Thoracic /..-')egments 

'These are much the same as in the adult, each bearing a pair ofjointed legs, and 

the second and third segments having externa] wing pads. l~he wing pads are closely 

pressed to the pleural region of the thorax. ]n C. modica and T. volda the wing pads 

extend as far as the fourth abdominal segment, and in A. latifascia to the fift.h 

abdominal segment. 

Legs: The pro- and mesothoracic legs are entirely free, and the metathoracic 

legs have the tibia and tarsus free. The pupal segments are similar to those ofthe adult 

except for the occurrence of an extra tarsal segment, nlaking six. The legs possess 

long swimming hairs. My observations with C. modica uphold I-lickin's statement 

that only the Iniddle legs are used for switn·ming, when the pupa swims to the surface 

of the water for the :final metamorphosis. l~he swimming hairs are best developed 

in the middle .legs, forming a double fringe of hairs along the length of the tibia and 

tarsus. 

Abdon1en 

Nine segments are present which are similar to those of the imago but are longer 

and luore flexible. 

In C. modica, S111all, bunched tracheal gills are present on abdolninal segments 

three to eight inclusive. As the time for emergence draws near the genitalia of the 

adult may be seen beneath the pupal skin. 

On the dorsum of the abdonlen are the sclerotized hook-bearing plates. In 

C 1 • n10dica these plates are present on segnlents one to eight inclusive. Seglnent three 

has an anterior and a posterior set of plates. On the third anterior and the fourth 

seglnental plates the hooks point anteriorly; on all other plates they point posteriorly. 

In T. volda hook-bearing plates are present on the posterior lnargins of segments 

two to six inclusive. The hooks of segment five point anteriorly, those of the 

other segn1ents being directed posteriorly. A. latifascia has plates only on segments 

one and five, and all the hooks point posteriorly. 

'The ninth abdominal seglnent bears processes armed with stout spines. '[here 

seelns to be general agreement as to the function of the anal appendages. They are 

used, like the spines on the labrunl, to keep the pupal case free from silt. 

The newly formed pupa of T. volda is CrealTI, of C. m.odica cream with greenish 

abdo111en, while in A. latifascia the thorax, head, legs~ and antennae are cream, and 

the abdolnen is orange with black lateral line and posterior ventral fringe.


Shortly before emergence, T. volda is dark brown, C. modica has dark brown 

wings and abdomen and a rich cream head, thorax, and legs, while A. latijascia 

has the head, thorax, legs, and abdomen pale yellow and the wings and antennae 

black. 

THE EXTERNAL ANATOMY OF THE ADULT OF Cheumatopsyche modica 

Head 

The head is wider than long, is hypognathous, and bears a number of setae. 

The compound eyes are conlparatively large and ocelli are absent. The frons is large 

and bears two areas of sensory spots, and the clypeus is well sclerotized and bulges 

slightly. The anterior tentorial pits are present at the lateral margins of the clypeus. 

The frons is a sub-rectangular area lying between the compound eyes and fonns the 

anterior part of the face. The genae, which Ineet the lateral margins of the clypeus, 

are also strongly sclerotized. They lie below the compound eyes and are drawn down 

ventrally into a hinge where the cardo articulates with the cranium. The labrum lies 

in the anterior arch of the clypeus, and the maxillae lie alongside the labrum. Three 

areas of sensory spots are present in the parietal region. Occipital and post-occipital 

sutures are present. The gular region is membranous and lies in loose folds near the 

cervix. 

The tentorium consists of anterior, dorsal, and posterior arlns which meet the 

cranium at the sides of the clypeus, at the inner angles of the antennaJ sockcts, and 

near the base of the postoccipital suture respectively. The tentorial body consists 

of a transverse bar below the pharynx. 

Antennae: Whcn at rest the antennae are held porrected in front of the head. 

They are inserted in the antennal sockets on the inner side of the compound eyes. The 

antennifer articulates with the outer side of the scape and is relatively prolninent. 

I'he scape is short, thick, and stumpy. Deoras (1940) is followed in calling the articulation 

at the distal end of the scape and the proximal end of the pedicle, which might 

he confused with the organ of Johnson, the "scapular peg". A projection is present 

on the inner side of the scape, and the antennifer and scapular peg give separate 

movelnents to the scape and flagel1um. The pedicle is a small segment, about one-third 

the length and half the width of the scape. l'he scape and pedicle are richly covered 

with hairs, and the scape bears small setae. The flagellum is filiform. 'rhe first flagellar 

segrnent is slightly shorter than the others. The flagellar seglnents bear regular rows 

of hairs, and a dark band is present at each flagellar joint. 1~he black curved bands 

which are present on the inner side of the first eight or nine flagellar segments in the 

genus Hydropsyche are absent in this genus. The flagellum has forty-three segments 

in the male and thirty-eight segments in the female. 

Mouthparts: The mouthparts are reduced in correlation with the non-feeding 

habits of the adults. The palps however are well developed. The labrum is short and 

broad and the Inandibles vestigial and non-functional, consisting only of a small 

mandibular piece. The cardo of the maxilla is reduced and covered by the stipes. 

The stipes articulates with a downward hinge-like projection of the gena. The stipes 

carries a lobe on the inner side and the palp on th.e outer side. The palps are fivesegmented 

and covered with hairs and setae. The first segment is stout and globular, 

the next three segments are ·more elongate, and. the distal segment is elongate, flexible, 

and tapering. '-fhe galea and lacinia are absent. 

Labium. The ligula is absent. The tip of the labium is a rounded sclerotized 

area which, according to Deoras (1940), represents the reduced mentum and sub 

Inentum. The labial palp is three-segmented, the distal segment being elongate. 

Hypopharynx. The hypopharynx of Imms and Tillyard is the haustellum of 

Deoras. I'he proxilna] rim of the hypopharynx is bordered by two curved sclerotized


hooks. The upper surface is covered by TIlinute hairs, and the salivary receptacle 

opens on the underside. According to Deoras, the "haustellulll" is the modified 

glossae and paraglossae of the ligula. 

Thorax 

The prothorax is small and ring-like, and the mesothorax is slightly larger than 

the nletathorax. The mesoscutum is divided mid-dorsally and is large and bulging, 

while the nletascutunl is smaller, triangular, and partly obscured by the first abdoTIlinal 

tergUTI1. The thoracic sterna are membranous. The propleurol1 is largely membranous, 

and the episternum is a slnall sub-triangular sclerite. The epimeron is a larger sclerite 

behind which lies the spiracle. The meso- and nletapleura possess clearly defined 

episterna and epimera, the latter being large rectangular sclerites.~ separated from the 

episterna by the pleural sutures, which arise from the basal coxal suture and end near 

the wing sclerites. The mesepisternulll is divided by a suture into an upper anepi.. 

sternum and lower katepisternulll. A large meron is present behind the meso- and 

Inetacoxae. 

Wings: The anterior wings are 7-8.5 mIll. long, relatively narrow, and are pale 

yellow, mottled with darker yellow and brown. They are extremely hairy, due to the 

presence of large microtrichja on the wing membrane and on the veins. The hind 

wing is 4.5-5.5 lllm. long) creamish sub-hyaline, and has a reduced clothing of hairs} 

but a fringe of long white hairs is present along the posterior margin. An amplexiforlll 

type of coupling apparatus is used in flight, a fold which runs the full length of the 

anallnargin of the fore wing engaging the costa of the hind wing. The thyridium may 

be seen on both wings as a smaH whitish spot devoid of hairs in the angle of the 

fork of R 4 + 5 • 1'he discoidal, Inedian, and thyridial cells are present in the fore wing, 

while the median and thyridial cells are absent in the hind wing. 

Venation of .Fore Wing. The wing venation is the same in the male and female. 

The length of the fore wing is eight mIll., and the length of the hind wing is five InlTI. 

The anterior margin of the wing is formed by the costal vein. More or less parallel to it 

runs the subcosta, linked to the costa at the base by the humeraJ cross vein, and 

terminating in the costa well before the apex of the \ving. The radius bifurcates near 

its base forIning RI and the radial sector, which also bifurcates, the two branches 

being joined by a cross vein to fornl. the discoidal cell. Both branches of the radial 

sector bifurcate to give R 2 to R s . 

The main stem ofthe ll1edia forks near the middle of the wing, the branches being 

joined by a cross vein to enclose the median cell. Each branch of the m.edia divides 

again before reaching the wing margin to give M I to M 4 • The large thyridial cell is 

closed by a llledio-cubital cross vein. This cross vein connects the main posterior 

branch of the media to the main stem of the cubitus. The cubitus forks near the wing 

margin to give Cu] a and CUI b. CU 2 is a strong vein joined to CUI by a cross vein. 

lA runs alm.ost the full length of the anal margin of the wing. 2A and 3A are small 

veins meeting lA near the base of the wing. 

Venation of the Posterior Wing. In the posterior wing a similar arrangement of 

veins occurs. The subcosta meets RI before the wing margin. The first branch of the 

radius and the second branch of the media are not forked. The three anal veins reach 

the wing margin, lA being the longest and 3A the shortest. 

Wing Articulation. In the fore wing the hUllleral sclerite is a small subtriangular 

sclerite on the anterior nlargin of the wing near the base. The base of the costa arises 

from this sclerite. The first axillary sclerite is broad posteriorly and narrows towards 

the apex as it approaches the subcosta. The first axillary sclerite is associated with 

the anterior notal process and is in close proximity to the base of the subcosta. 

The second axillary sclerite articulates partly with the base of the radius and is 

closely associated with the first axillary sclerite and the posterior median plate.

18 KATHERlNE KORBOOT 

The third axillary sclerite articulates with the posterior notal process and is a long 

relatively thin sclerite. Jt is associated with the anal veins. The median plates are 

large lightly sclerotized areas. The tegulae are small, scale-like, hairy sclerites carried 

at the extreme base of the costa of each fore wing. 

In the hind wing the articular sclerites are In uch the same as in the fore wing, 

but the median plates lie behind and not beside each other. 

Legs: The legs are long and used for running. The coxae are relatively 

elongate, and the mid coxa has a partially sclerotized posterior meron. The trochanter 

is s1l1all and bears a s.tnall characteristic black dot. The felnur and tibia are 

long and slender. The fore tibia bears one pair of apical spurs, the mid and hind 

tibiae bear one pair of apical and one pair of TIliddJe spurs. l'he tarsi are fivesegmented 

and end in a pair of very slnall claws. Between the claws is a small 

cushion-like empodiullL 

Abdomen 

The abdomen is lnore or less cylindrical and is ten-segmented. Each segment 

bears a pair of spiracles, those of seglnents three to eight inclusive being readily 

found in the male, and of three to seven inclusive in the female. Wide pleural 

membranes separate the tergites and sternites of the first seven segments in the 

female and the first eight seglnents in the lllale. The rudiments of the tracheal gills 

are seen as dark purple 111asses on either side of segments three to eight inclusive. 

Male External Genitalia: An adequate description of the nlale external genitalia 

is given by Mosely and KiJnmins (1953). 

female External Genitalia: The eighth tergum does not differ greatly from 

the other terga but it bears a linear median division, the posterior margin being lobe... 

like. A sub-genital plate is absent. The eighth sternum is completely divided, fonning 

two large sclerotized valvular structures, the 'posterior margins of which bear long 

hairs. The ninth tergum is small, with the lateral .tnargins produced downwards, 

and the ninth sternum forms a small median plate. The genital opening is between the 

eighth and ninth sterna, and is both egg-laying and copulatory in function. The 

tenth seglnent is small, fleshy, and lobe-like and bears six digit-like, chitinous appendages. 

Two bristles and nUlnerous hairs are present on the tenth segll1ent. 

SOME POINTS OF COMPARISON BETWEEN THE EXTERNAL MORPHOLOGY OF 

Cheumatopsyche modica, Triplecfides volda, AND Anisocentropus lat(fascia 

In the three species the head is wider than long, and ocelli are absent. 

In relation to the size of the head, the frons is largest in A. lat~fascia where it 

occupies most of the posterior part of the head. The frons of T. volda bears one patch 

of sensory spots, such spots being absent in A. latifascia. The occiput may be seen in 

all cases, but the postocciput is not broadly visible in C. modica and A. latifascia 

as it is in T. volda, where it occupies the whole qf the back of the head. The clypeus 

is arched posteriorly, but in T. volda lateral posterior expansions extend at the sides 

of the antennae. The clypeus is snlallest in C. modica. In the three species the genal 

region is a large sclerotized area below the eyes and forms a hinge where the maxilla 

articulates with the cranium. The gular region is membranous. 

The antenna of T. volcla is 1110re than twice as long as the fore wing, with one 

hundred flagellar seglnents in the fetnale and one hundred and six in the male. In 

A. latljascia the antenna has forty-five flagellar segnlents in both sexes and is nearly 

twice the length ofthe fore wing. In T. volda the scape is large, thick basally, and tapering 

distally. The pedicle .is small, and the flagellar segll1ents long and narrow. A ring


of white hairs is present distally on each flagellar segment. The scapular peg is ill... 

defined. In A. latifascia the scape is elongate, the pedicle small and globular, and the 

flagellar segments elongate. The head and antennae are covered with yellow hairs. 

The labrum of T. volda is elongate distally and bulged proxin1ally. There is a 

more prominent constriction between the proximal and distal ends than in the case of 

C. modica, but as in C. modica and A. latifascia the labrum is well sclerotized. In 

A. lat(fascia the constriction divides the labrum into two rectangular halves, the distal 

being the smaller of the two. 

In the three species the mandibles are vestigial and in A. lat~fascia appear to be 

totally lacking. In T. volda the maxillary palps are five-segn1ented in both sexes as in 

C. Jnodica, but in A. latifasoia they are six-seglnented, the -sixth segment being very 

short. The last segnlent of the palp in T. volda and A. latlfascia is not elongate and 

flexible. T. volda and A. latifascia are alike but differ from C. rnodica in that the stipes 

is reduced to a slnall band-like sclerite and the small cardo articulates with the hinge 

of the gena. The lobe of the maxilla is largest in T. volda and in T. volda and 

A. latifascia bears stout bristles and sensory spots. 

The tip of the l11.embranous labiu111 area is sclerotized and is rounded in C. modica 

and T. volda, but pointed and triangular in A. latifascia. The proximal seglnent of the 

three-segmented labial palps in the three species is situated on a raised node-like 

sclerite. In C. modica these nodes are joined at the base, but in T. volda and A. latifascia 

they are isolated from each other on either side of the sc]erotized tip of the labiuIT1. 

The hypopharynx is greatly reduced in C. n20dica and A. latifascia. In T. volda 

it is a wen-developed, pouch-like, hollow lobe, the upper surface of which is covered 

with minute hairs and regular radiating channels which bifurcate distally. 

In the three species the prothorax is small, narrower than the head, and ring-like' 

and in T. volda and A. latlfascia it bears a nledian dorsal suture as in C. modica. 

In T. volda and A. latifascia the mesoscutunl is not divided mid-dorsally, as in 

C. modica, but is large and bulging and forms the largest thoracic sclerite. In 

A. latifascia two longitudinal ilnpressions mark off a central portion from two lateral 

portions. 1'he mesoscutellum is the largest in T. volda, while the nleso-postnotal 

sclerite is the largest in A. lat~fascia, where the pleural membranes are not visible 

dorsally in this region. The metascuium and scutellulll are sin1ilar in the three species. 

The meso- and metapIeural sclerites are large and sub-rectangular in all three, but in 

T. volda and A. latifascia the mesepisternum is not divided. In A. latifascia the 

metepisternulll is divided into an upper anepisternuln and a lower katepisternurn. 

The mesopleural suture of A.' latifascia is a rnembranous area separating the mesopleural 

sclerites. 

The arrangement of the tibial spurs of A. lafijascia differs from that of C. modica 

and T. volda. T'he fore tibiae bear two small spurs at the apex; the Inid tibiae bear 

two spurs at the apex and two in the middle, the outer spur of each pair being long; 

the hind tibiae have one long spur in the lniddle and two unequal ones at the apex. 

In 1'. volda and A. latifascia, as in C. modica, a snlall cushion-like empodiunl is 

present between the claws of the pretarsus. 

N-o gill rudirnents are present on the abdomens of T. volda and A. lat(fascia 

as they are in C. modica. 

In T. volda abdominal spiracles are visible on segments three to eight in the 

pleural membranes. A. latifascia differs from T. volda and C. modica in that the 

spiracJes are visible on segments one to eight in the pleural melubranes. The abdonlen 

of A. latifascia is black in colour and bears a characteristic pattern on terga two to 

eight. 

In A. latifascia the wings are coloured grey-black and yellow. No clear colour 

change is visible between the base and apex of the wing, yellow merging into black


at the base. (It is interesting to note that the yellow band which occupies the basal 

half of the fore wing of A. elegans does not develop fully until twenty-four hours 

after emergence.) The hind wings are 6-7 mm. in length, and the fore wings are broad, 

obliquely rounded at the apex, and 7-811nm. in length. The hind wing shows a striking 

character which according to Mosely and Kimmins (1953) may be generic. The area 

immediately posterior to vein CUIa is clear, the veins CUlb and Cu 2 , which normally 

occupy this area, being virtually obliterated. The venation is the same in the male 

and the female. 

The wings ofT. volda are a pale brown covered with short white and brown hairs' 

The fore wings are 11-12.5 Inm. long, and the hind wings 7-8 mm. long. The venation 

of the fore wing of the male and female differs slightly. The discoidal cell is longer in 

the fe.111ale, and veins M 1 and M 2 are not fused as they are in the male. 

THE INTERNAL ANATOMY OF THE AD1.JLT OF Cheum.atopsyche modica 

Dissection Technique 

The specimens to be dissected were treated in one of the following fixatives· 

Carnoy, Bouin, or Mosely's (1939) collecting fluid. Fixation in Carnoy gave the most 

satisfactory general results, and was suitable for the dissections of the reproductive 

systeln and tnicrotome work by paraffin embedding. Bouin's 'fixative was suitable 

for dissection of the nervous and digestive systems. Mosely's collecting fluid was not 

so efficient. After fixation the insects were preserved in 70 per cent alcohol. 

The anatomical studies were carried out by dissections under high power lnagnification 

assisted by 8 to 10 /-L microtome sections. The figures were drawn either from 

microscopical preparations or direct dissections. In the former they are drawn to 

scale, while in the latter they are semi-diagrammatic. 

Digestive .C;ystem 

.~alivary glands. The salivary glands are well developed and consist of a number 

of irregularly arranged tubules which lie on either side of the oesophagus in the 

first and second thoracic segments. The main duct lies within the heap of tubules 

in the first thoracic segment and is alongside the ventral nerve cord, which supplies 

the duct with a small nerve. The two ducts unite in the gular region and pass into a 

slnall salivary reservoir which opens on the underside of the hypopharynx. The Inain 

salivary duct is slightly shorter than the oesophagus. 

Alimentary Canal. Within the Inouth is a chitinous ring, which is supported 

by the proximal part of the hypopharynx and the lower part of the labrum. It leads 

into a wide muscular pharynx. The oesophagus is a very thin, semi-transparent tube 

and is surrounded by the pale yellow fat bodies. The oesophagus leads into the 

lllenlbranous crop, which is very large and sac-like and extends to the third abdominal 

segnlent. In a freshly killed specimen the crop is dilated with air and probably 

functions as an aerostatic organ. 

The proventriculus is very short and consists mainly of the anterior sphincter 

lTIuscles, followed by a number of long fine teeth which project into the lumen of the 

mid-gut. The mid-gut is more thickly walled than the crop and is darker in colour. 

It begins in abdominal segment "five. The dark colouration, according to Deoras, 

is due to the presence of piglnented matter enclosed in a membrane. T'he mid..gut is 

slnaller than the crop but is again sac-like, and gastric caeca are wanting (as is to be 

expected in adults which feed little and then only on a liquid diet). The mid-gut is 

folded on itself, so that its posterior end lies close above its anterior end. 

At the junction of the :mid- and hind-gut are six Malpighian tubules arranged 

irregularly around the gut. The length ofthe tubules varies from nine to fourteen mnl., 

and their colouration is greyish green. The hind-gut is almost straight, longer than


the mid-gut, and is again thicker and more darkly coloured than the oesophagus. 

The rectum however is Inembranous, wider than the rest of the hind-gut, and globular 

in shape. Six opaque patches, the rectal papillae, are arranged in a row round the 

circumference of the rectum. Glasgow (1936) describes these papillae in Ifydropsyche 

colonica as being large swellings, almost filling the gut lumen, each being subhemispherical 

with four or five big nuclei. 

The alimentary canals of adults which had been bred from pupae and kept alive 

for a nUlnber of days in a breeding cage were found to be free from food contents, 

but in all cases the crop was dilated with air. The alimentary canals of specimens 

caught in the field often contained liquid nutrients, and the rectum of such specimens 

often contained small alnounts of faecal material. 

Central Nervous System 

The cerebral ganglion is conspicuous by the presence of the large optic lobes at 

its sides. The protocerebrum is bilobed and gives off a small median nerve and a pair 

of very fine nerves which run out laterally. Froil1 the deutocerebrum arises a pair of 

thick antennal nerves. The deutocerebrunl runs forward to meet the frontal ganglion 

in front of the arch of the brain. Posteriorly the deutocerebrum gives off a pair of 

nerves to the occipital ganglion. The tritocerebrum is continued ventro-Iaterally as 

thick circum..oesophageal connectives to join the large sub...oesophageal ganglion. 

A transverse nerve joins the connectives. 

A large nUlnber of nerve fibres arise from each side of the pyriforlTI suboesophageal 

ganglion. A short nerve runs anteriorly to the reduced mandible. The 

large second nerve fibre, which arises ventro-Iaterally and bifurcates shortly after 

leaving the sub-oesophageal ganglion, innervates the Inaxillary palp. Three more 

pairs of nerves may be traced from the sub-oesophageal ganglion. 'The first is long 

and supplies the labial region. The second is short and supplies the hypopharynx, 

and the third the cervical region. Dorsally, a short fine nerve supplies the oesophagus. 

The connectives between the sub-oesophageal ganglion and the first thoracic ganglion 

are paired and give off a pair of nerves to the main salivary duct. 

The mesothoracic ganglion is the Iargest of the thoracic ganglia, but in Plate 13, 

F'ig. 1, it appears smaller than that of the prothorax as it is laterally cOlnpressed 

between the legs, so that the nerve branches issue ventro-Iaterally. 'The connectives 

between the pro- and mesothoracic ganglia are paired, but those between the lnesoand 

metathoracic ganglia are fused. 

Three Inain pairs of nerves arise from the prothoracic ganglion. One pair supply 

the first pair oflegs, one pair the tubules of the salivary gland, and one pair the general 

musculature of the segment. Three main pairs of nerves also arise fronl the mesothoracic 

ganglion, one pair supplying the legs, one the wing sclerites, and one the 

general musculature of the segment. Two pairs of nerves arise from the metathoracic 

ganglion, one pair supplying the legs and one the general musculature of the segment. 

The first to fourth abdominal ganglia are small and lie in the anterior part of their 

respective segments. The fifth and sixth ganglia lie close together in the fifth segment. 

The sixth ganglion is large, and probably represents a fusion of the ganglia of the 

sixth, seventh, and eighth segnlents. All the abdominal ganglia are connected by paired 

longitudinal connectives and give o.ff nerves to the body wall and viscera. The nerves 

from the sixth ganglion are the longest and thickest, and extend to the last abdominal 

seglnent. 

Oesophageal Sympathetic Nervous System 

The frontal ganglion is a narrow band-like ganglion and lies below the clypeus. 

Fine nerves are given off anteriorly to the labrum, and short stout nerves connect the 

frontal ganglion to the deutocerebrum. :Posteriorly the recurrent nerve runs along the


side of the pharynx until it Ineets the occipital ganglion behind the deutocerebrum. 

The occipital ganglion also receives fine nerves from the deutocerebrum and gives off 

the two fine recurrent nerves posteriorly. The latter meet the small corpora cardiaca 

on the oesophagus and ramify over the crop. The nerve connections between the 

corpora cardiaca and the occipital ganglion could not be determined. The occipital 

ganglion is connected by short thick connectives to the corpus allatum of each side. 

The corpora allata are double structures lying on either side of the aorta, and 

connected to the corpora cardiaca by fine nerves. The edges of the lobes of the 

corpora allata are slightly convoluted. 

Male .Reproductive System 

The testes are con1pact lobulated bodies lying in the seventh abdominal segn1ent. 

Each testis has a sac-like covering and each lobe is joined by a short vas efferens to 

a small central chan1ber of the testis. The vas deferens is a long coiled tube of greater 

width but less transparency than the Malpighian tubules. The accessory glands are 

n1embranous pyriform sacs and occupy lYl.uch of the seventh and eighth abdominal 

seglnents. They were found to be full of the amber coloured crystals that are m.entioned 

by Deoras. The accessory glands lie next to the testis of their side and open without a 

duct into the vas deferens. 'Beyond its junction with the accessory gland the vas 

deferens opens into a crealnish-coloured unpaired accessory gland which enlarges 

into - a stout seminal reservoir (vesicula seminalis).The nledian ejaculatory duct 

(ductus ejaculatorius) is covered by a muscular sac and leads into the penis duct 

which is directed downwards. The penis is thick and fleshy and covered proximally 

by a chitinous sheath. 

[n this species there seems to be a tendency towards shortening of the vas deferens 

and simplification of the male reproductive organs. 

;"female Reproductive System 

The ovaries are situated in the fIfth abdolninal segment and look like two large 

cream raspberries. 1'hey consist of a large number of sInall acrotrophic ovarioles 

grouped together into a calyx. The ovaries open into narrow, paired oviducts which 

fuse in the midline to form a stout 'median oviduct (oviductus cOD1munis). The 

pear-shaped gland is a small, round Inembranous sac lying beside the median oviduct 

and opening into it by a slender duct. T'he pear-shaped gland was found to contain a 

transparent fluid. It was considered by Stitz (1904) to be the receptacululn sem.inis, 

but according to Cholodkovsky (1913) it is a glFtnd of unknown function. 

The bursa copulatrix is also a men1branous sac but is larger than the pearshaped 

gland. The narrow duct (ductus bursae), fronl the bursa copulatrix, joins the 

duct from the pear~shaped gland before the latter opens into the median oviduct. 

The bursa copu1atrix was a deep cream in colour and in a nUlnber of cases was found 

to contain a small amount of viscous material. The bursa copulatrix bears a long 

tubular structure at its proximal end. This structure was called the "flagelluln" by 

Stitz, but it js shown by Cholodkovsky that it functions as a receptaculum seminis. 

Behind the opening of the pear-shaped gland duct and the ductus bursae, opens 

the con1ffion duct of the colleterial glands. The colleterial glands are long, wide 

tubes joined at the base by a broad transverse connective. T'hese glands were full of a 

clear mucilaginous material. T'he tertninal part of the genital chamber is relatively 

long and lnuscular. 

SOME POINTS OF COMPARISON BETWEEN THE INTERNAL ANATOMY 

OF THE ADULTS OF Cheun1atopsyche modica, Triplertides volda, 

AND Anisocentropus latifascia 

Digestive S"1ystem 

S"1alivary Glands. In T. volda the structure of the salivary glands is similar to 

that of C. modica, but the tubules are extremely fine, and the main duct is a1n10st


indistinguishable. In A.. latifascia the tubules are absent altogether, but the salivary 

duct is a prominent structure. 

Alimentary Canal. In T. volda the oesophagus is shorter than that of C. modica 

but of about the same width. In A.. latifascia the oesophagus is very long and extrelnely 

narrow. In T. volda the crop is sac-like and is smaller than that of C. lnodica even when 

fully dilated. A. latifascia has a cylindrical crop which is the smallest of the three 

species. ]n all cases the proventriculus is very short and hardly distinguishable. The 

mid-gut of T. volda tapers posteriorly and is slightly larger than the crop. The mid-gut 

of A. latifascia is smaller than that of T. volda, but its surface is folded. In T. volda 

the hind-gut and rectulll do not differ from those of C. rnodica, but in A. latisfacia 

the hind-gut is a coiled tube and the rectulTI. is more extensive..1n all species there 

are six Malpighian tubules and six rectal papillae. 

Nervous Systenl 

l~he cerebral ganglion is sinlilar in the three species. The optic lobes are the largest 

in T. volda and the smallest in C. n10dica. T. volda has five abdominal ganglia, the 

flfth being fused with the sixth. In A. latij'ascia there are six abdominal ganglia as in 

C. modica, the fifth and sixth being nlore equal in size than in C. modica. In all 

species the last abdominal ganglion gives off nerves which reach the last abdonlinal 

segment. In T. volda and A. latifascia the connectives between the m,eso- and metathoracic 

ganglia are not fused as they are in C. modica, but in T. volda the posterior 

longitudinal connectives have coalesced. 

There are few outstanding peculiarities in the oesophageal synlpathetic nervous 

system of the different species, except .for differences in shape and size of the corpora 

allata. These are relatively the largest in C. modica and Inuch reduced in T. volda. 

In C:. modica and A. latifascia they are similar in size but in A. latifascia they are more 

lobulated. 

,Male Reproductive System 

In 1'. volda the testes consist each of three small, separate lobes, the paired 

accessory gland being larger than the testis. The vas deferens is longer and lnore 

convoluted than that of C. modica. 1'he unpaired accessory gland and vesicula 

senlinalis are similar in C. modica, T. volda and A .latijascia. In I'. volda the ejaculatory 

duct is long. In A. lat(lascia the testes are slllall, sim,ple, rounded bodies, the -paired 

accessory gland is a large pyriform Inelnbranous sac, and the vas deferens and 

ejaculatory duct are very long. 

Felnale Reproductive System. 

In T. volda the ovaries are much smaller than in C. lnodica and consist of about 

fifteen acrotrophic ovarioles. The paired oviducts are narrow. l'he pear-shaped gland 

and bursa copulatrix are sinlilar to those of C. nzodica, but the tubular structure of 

the bursa was not found. The colleterial glands are very long and narrow. rn 

A. latifascia the ovaries consist of a large number of polytrophic ovarioles grouped 

together on a long calyx, the calices opening onto very short, paired oviducts. The 

terminal filaments 111eet to [orln a suspensory ligalnent. The pear-shaped gland is 

similar to that of ~r. volda and (;. nzodica, but the bursa copulatrix is the largest. of the 

three species. A.gain the tubular structure of the bursa was not found. '"[he colleterial 

glands are large and tubular.


REFERENCES 

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CHOLODKOVSKY, N. (911). Zur Kenntnis des mannlichen Geschlechts-apparates der Trichopteren. 

Z. wiss. InsektBiol. 7: 384-85. 

DAS, G. M. (1937). The nlusculature of the mouth-parts of insect larvae. Quart. J. micro Sci. 80: 39-80. 

DEORAS, P. J. (1940). Comparative morphology and evolution of adult Trichoptera. Part 1. Indian 

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Du PORTE, E. M. (1957). The comparative morphology of the insect head. Ann. Rev. Ent. 2: 55-70. 

GILSON, G. (1894). Recherches sur les cellules secretantes. La soie et les appareils sericigenes. 11. 

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GLASGOW, J. P. (1936). Internal anatolny of a caddis (Hydropsyche colonica). Quart. J. micro Sci. 

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HICKIN, N. E. (1946). Larvae of British lrichoptera (key to families). Trans. roy. ent. Soc. 97: 186-212. 

HICKIN, N. E. (1949). Pupae of British Trichoptera and SOlne other insects. Irans. toy. ent~ Soc. 

100: 275-89. 

fIINTON, H. E. (1946). A new classification of insect pupae. Proc. zool. Soc. Lond. 116: 282-328. 

TMMS, A. D. (1957). A General Textbook of Entomology. London: Methuen. 

KLAPALEK, F. (1889). The metamorphosis of Apatoenia muliebris McLachlan. A chapter in parthenogenesis. 

E'nt. nlon. Mag. 24: 241-42. 

KRAFKA, J. (1923). Morphology of the head of Trichopterous larvae as a basis for the revision of 

family relationships. I. N. Y. ent. Soc. 31: 31-52. 

LESTAGE, J. A. (1921.). Chapter in Rousseau, E. (1921). Larves et Nymphes Aquatiques des Insectes 

d~Europe. Brussels. 

LLOYD, J. T. (1921). North American caddis fly larvae. Bull. Lloyd Libr. 21: 3-124. 

LDBBEN. H. (1907). Deber die innere Metamorphose del' Trichopteren. Zool. Jb. 24: 71-128. 

MAcDoNALD, N. W. (1950). The larvae of Mystacides aZllrea L., Cyrnus ffavidus McLachJan and 

Oxyethria simplex Ris (Trichoptera). Proc. roy. ent. Soc. Lond. Series A. 25: 19-28. 

MARSHALL, W. S. (1907). The early history of the cellular elements of the ovary of a Phryganid, 

Platyphylax designatus Walk. Z. wiss. Zool. 86: 214-37. 

MOSELY, M. E. (1939). The British Caddis Flies (Trichoptera): a Collector's Handbook. London: 

Routledge. 

MOSELY, M. E. & KIMMINS, D. E. (1953). The Trichoptera (Caddis Flies) ofAustralia and New Zealand. 

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ORCUTT, A. W. (1934). The caddis flies or l'richoptera of the N.Y. State. Bull. N. Y. St. Mus. 292: 

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VORHIES, C. T. (1905). Habits and anatomy of the larvae of the caddis fly Platyphylax designatus 

Walk. Trans. Wis. A cad. Sci. Arts Left. 15: 232-244. 

ZANDER, E. (190J). Beitrage zur Morphologie der mannlichen Geschlechtsanhange der Trichopteren. 

Z. wiss. Zool. 70: 192-235.

THREE SPECIES Of CADDIS fLIES (TRICHOPTERA) 

2S 

a 

b 

c 

d 

e 

f 

g 

h 

i 

j 

k 

1 

n1 

n 

o 

p 

q 

r 

s 

t 

u 

labrum 

mandible 

maxilla 

labium 

coxa 

tibia 

trochanter 

pretarsal claw 

femur 

tarsus 

eye 

fronto-clypeus 

pronotum 

mesonotum 

metanotuln 

dorsal tubercle 

subdorsal gill 

episternun1 

epimeron 

pleural suture 

lateral tubercle 

KEY TO F'IGURES 

LARVAL EXTERNAL ANATOMY 

(Plates 1, 2, 3, 10, 11) 

V 

W 

x 

y 

z 

a 

l 

e l 

gl 

hI 

i ' 

j I 

k ' 

I 1 

nl 

n 

o 

pI 

ql 

r l 

SI 

t l 

lateral line 

subventral gill 

lateral gill 

anal appendage 

claw 

vertex 

gular suture 

gular sclerite 

mouthparts 

nlaxillary palp 

ligula and spinneret on prementum 

inner lobe 

stipes 

cardo 

postLnentum 

T-shaped anus 

abdonlinal seglnent nine 

stout bristles 

subdorsal gill 

epicranial suture 

ante-clypeus 

a 

b 

c 

d 

e 

f 

g 

h 

i 

j 

k 

I 

In 

n 

o 

p 

q 

r 

st 

u 

v 

w 

x 

y 

proventriculus 

stomodaeal invagination 

mid-gut 

lateral Malpighian tubule 

crop 

ventral Malpighian tubule 

oesophagus 

silk gland 

dorsal Malpighian tubule 

pharynx 

small intestine 

buccal cavity 

large intestine 

rectum 

silk gland duct 

sub-oesophageal ganglion 

silk gland proper 

Gilson ~s gland 

alimentary canal 

aorta 

dorsal blood vessel 

alary muscle 1. 

alary muscle 9. 

filament 

gonad 

LARVA(J INTERNAL ANATOMY 

(Plates 3, 4, 5, 6, 16) 

z 

a I 

duct 

supra-oesophageal ganglion 

b I prothoracic ganglion 

Cl Inesothoracic gangl ion 

d I metathoracic ganglion 

e I first abdominal ganglion 

f' 

g I 

fourth abdominal ganglion 

sixth abdonlinal ganglion 

h I 

i I 

eighth abdolninal ganglion 

optic nerve 

j I lateral nerve 

k I antennal nerve 

1 nerve to front of head 

In I mandibular nerve 

n I frontal ganglion 

o I labial nerve 

p I 

ql 

recurrent nerve 

intima 

1'1 epithelium 

s I nucleus 

t I pignlent 

u I oesophageal ring 

v I labial nerve 

w = l 

maxillary nerve 

x I = intestine 

a 

b 

c 

d 

e 

f 

g 

h 

antenna 

compound eye 

pronotum 

mesonotum 

fore wing pad 

nletanotum 

hind wing pad 

anal process 

PUPAL ANATOMY 

(Plates 5, 6, 7) 

i 

j 

k 

1 

nl 

n 

o 

pretarsal claw 

tarsal segment six 

tarsal seglnent five 

dorsal hook-bearing platt 

abdominal segnlent eight 

abdominal segment nine 

anal process


ADULT EXTERNAL ANATOMY 

(Plates 7, 8, 9, 10, 11, 12) 

a antenna p' chitinous rod 

c clypeus q' median scutalline 

d compound eye r' pleural membrane 

f frons s' nletascutum 

g pronotum t' metascutellum 

h tegllla u' head 

i mesoscutum v' epimeron 

j mesoscutellum w' episternum 

le meta-postnotum Xl pleural suture 

1 nletanotum yl sensory hairs 

m abdomen z' outer side of mandible 

n clasper a" inner side of mandible 

b" base of mandible 

Cl' ginglymus 

0 aedeagus 

Rc= discoidal cell 

q median cell d'l 

r thyridial cell e" 

femur 

coxa 

middle spurs 

trochanter 

u scape h ll tibia 

v maxillary palp i" fine hairs 

w gena y' apical spurs 

x labrum k 'l tarsus 

y lobe of Dlaxilla I" claws 

z mandibular piece rn":= abdorninal tergum 8 

a l hypopharynx nil abdominal tergum 9 

b' labial palp 0" abdominal seg.nent 1O 

c' occiput pi' digital processes 

d' post-occiput q~' abdonlinal sternum 8 

e l second flagellar segment r abdo111inal sternunl 9 

s 

t 

thyridium 

apical fork 

f" 

g" 

fl 

first flagellar segment 

Sll 

cervical sclerite 

g' pedicle fl 

humeral plate 

h' 

i' 

antennifer 

proximal bulging of labrum 

U ll Vi' 

first axillary scleri tc 

second axillary sclerite 

j' outer side of labrum W ll anterior notal process 

k l distal bulging of labrulll Xl' anterior median plate 

l' base of labial palp y" =--. posterior median plate 

m / = reduced labiunl 

n l second segment of maxillary palp z" third axillary sclerite 

0' :::c= lobe of maxilla a"I= posterior notal process 

a 

b 

c 

d 

e 

f 

g 

h 

i 

j 

k 

1 

M 

n 

o 

p 

qrs 

nlo11th 

salivary reservoir 

pharynx 

salivary duct 

oesophagus 

salivary ductules 

crop 

tip of proventriculus 

mid-gut 

Malpighian tubules 

hind-gut 

rectum 

rectal papilla 

anus 

antennal nerve 

peduncle to nledian ocellus 

arch of brain 

optic lobe 

nerve connective from frontal ganglion 

to deutocerebrull1 

ADULT INrERNAL ANATOMY 

(Plates 12, 13-15, 16) 

t 

u 

v 

w 

x 

y 

z 

a,' 

posterior connective 

para-oesophageal connective 

mandibular nerve 

maxillary nerve 

sub-oesophageal ganglion 

labial nerve 

hypopharyngeal nerve 

nerve to the salivary gland and gular 

region 

lateral ocellar nerve 

occipital ganglion 

corpus allatllm 

aorta 

recurrent nerve 

nerve to oesophagus 

upper lobe 

convoluted margin 

lower lobe 

nerve to occipital ganglion fronl 

deutocerebrUlTI

and 


m / = cephalic ganglion g" ovariole 

n l = nerve to main salivary duct h" paired oviduct 

0 1 ill 

= first double longitudinal connective bursa copulatrix 

pI· prothoracic ganglion j" colleterial gland 

ql mesothoracic ganglion k" pear-shaped gland 

r l fused 

4 

connectives between nleS0 1" spernlathecal duct 

nletathoracic ganglia 

m" =: junction of spermathecal duct, shell 

s' Inetathoracic ganglion gland duct, and median oviduct 

t l fifth abdo111inal ganglion n" transverse connection of colleterial 

u l sixth abdolninal ganglion glands 

VI nerves reaching last abdonlinal segment 0" genital chamber 

w' anterior nerve p" corpus cardiacunl 

Xl 

frontal ganglion q" circum-oesophagea1 COlnlTIissure 

y~ ventral lobe of frontal ganglion r" first abdominal ganglion 

z testes t" ductus bursae 

a" vesicula seminalis u" cuticular calyx 

bl! paired accessory gland v" tubular structure of bursa copulatrix 

C ll 

unpaired accessory gland 

w" sperm sac 

d ll 

vas deferens 

XII 

e" ejaculatory duct 

protein mass 

f" ovary y" tcnninalligament 

LEGENDS To PLATES 

PLATE l.--Larval external anatomy. 

Figs. 1-3, dorsal and ventral aspects of heads: (1) C. 111Odica; (2) T. volda; (3) A. latifascia. 

Figs. 4-6, dorsal aspect of labrum: (4) (~. lnodica; (5) J'. volda; (6) A. latlfascia. Figs. 7-9, mandibles: 

(7) C. J1JOdica; (8) T. volda; (9) A. latifascia. Figs. 10, 11, head of C. lnodica: (l0) ventral aspect; 

(11) lateral aspect. Figs. 12, J3, nlaxilla and labiulll: (12) T. volda; (13) A. latifascia. Figs. 14-16, 

dorsal view of anal clasper: (14) (7. lnodica; (15) T. volda; (16) A.latifascia. Figs. 17-19, ventral view 

of anal clasper: (17) C. lnodica; (18) T. volda; (19) A. latifascia. 

PLATE 2.-Larval external anatomy. 

Figs. 1-3, dorsal aspect of thorax: (1) C. lnodica; (2) T. volda; (3) A. latifascia. Figs. 4-6, lateral 

aspect of anal claspers: (4) C. modica; (5) T. volda; (6) A. lat/fascia. Figs. 7-9, fore, n1id, and hind 

legs of C". modica. Figs. 10-12, fore, Inid, and hind legs of T. volda. Figs. 13-15, fore, n1id, and hind 

legs of A. latifascia. l-=


PLATE 7.-Pllpal external anatomy (Figs. 1-4, 8-(3). PrepupaI anatomy (Figs. 5-7). Adult external 

anatomy (Figs. 14-18). 

Fig. 1, dorsal aspect of pupa of A. latifascia. Figs. 2-4, mandibles: (2) C. Inodica; (3) T. volda; 

(4) A. latifascia. Figs. 5-7, mesotarsal claw: (5) C. modica; (6) T. volda; (7) A. latifascia. Figs. 8-10, 

C. mod/ca: (8) dorsal aspect of ninth abdominal segment; (9) ventral aspect of ninth abdominal 

segment; (10) ventral aspect of ninth abdominal segment showing curling of antennae. Fig. 11, 

dorsal aspect of ninth abdominal segment of A. latifascia. Figs. 12~ J3, T. volda: (12) dorsal aspect of 

ninth abdominal segment; (13) ventral aspect of ninth abdominal seglnent. Figs. 14- J8, C. lnodica: 

(14) front view of head; (15) dorsal view of head; (16) dorsal view of female terminalia; (17) ventral 

view of female terminalia; (18) lateral view of female terminalia. 

PLATE 8.-Pupal anatomy (Figs. 1-3). Adult external anatomy (Figs. 4-14). 

Figs. 1-3, dorsal abdominal hook-bearing plates: (1) C:'. modica; (2) T. volda; (3) A. latlfascia. 

Figs. 4-14, C. modica: (4) basal section of antenna; (5) labium; (6) labrum; (7) pronotunl; (8) maxilla; 

(9) lateral view of abdomen; (10) meso- and metanota; (11) propleuron; (12) 111eso- and metapleura; 

(13) fore leg; (14) mandible. 

PLATE 9.-Adult external anatomy. 

Figs. 1, 2, T. volda; (1) hind leg; (2) dorsal view of head. Figs. 3-5, C. F11odica: (3) mid leg; 

(4) lateral view of head; (5) right fore wing. 

PLATE 10.--Adult external anatomy (Figs. 1-12, 15-J9). Larval external anat01l1Y (Figs. 13, 14). 

Fig. 1, right hind wing of C. nl0dica. Figs. 2, 3, front view of head: (2) T. vo/da: (3) A. latzfascia 

Fig. 4, dorsal view of head of A. latifascia. Figs. 5, 6, basal section of antenna: (5) A. latifascia; 

(6) T. volda. Figs. 7-9, labrum: (7) A. latzfascia; (8) T. volda; (9) T. volda. Fig. 10, labium of 

A. latifascia. Figs. 11, 12~ maxillary palp: (11) T. volda; (12) A. latifascia. Fig. 13, lateral view of 

prothorax of C. nlodica. Fig. 14, lateral view of mesothorax of C. modica. Figs. 15, 16, meso- and 

Inetaterga: (15) T. volda; (16) A. latifascia. Fig. 17, lateral view of abdomen of A. latifascia. Fig. 18, 

dorsal view of abdominal tergites one to four of A. latifascia. Fig. 19, meso- and metapleura of 

T. volda. 

PLATE 1] .-Adult external anatonly (Figs. 1, 7-16). Larval external anatomy (Figs. 2-6). 

Fig. ], meso- and metapleura of A. latifascia. Figs. 2, 3, lateral view of prothorax: (2) J~. volda; 

(3) A. latifascia. Figs. 4, 5, lateral view of mesothorax: (4) A. latifascia; (5) T. volda. Fig. 6, lateral 

view of metathorax of A. /anfascia. Figs. 7-9, 1~. volda: (7) fore leg; (8) mid leg; (9) hind leg. Figs. 

10-12, A.latifascia: (10) fore leg; (11) mid leg; (12) hind leg. Figs. 13, 14, propleuron: (13) C. lnodica; 

(14) T. volda. Fig. 15, right fore and hind wing of T. volda (male). Fig. 16, dorsal view of right fore 

wing of C. F1lOdica showing wing articulation sclerites. 

PLATE] 2.-Adult external anatomy (Figs. 1, 2, 4). Adult internal anatomy (Figs. 3, 5). 

Fig. 1, right fore and hind wing of A. latzfascia. Fig. 2, rigl1t fore wing of T. volda (female). 

Fig. 3, position of spermatophore in bursa copulatrix of C. modica. Fig. 4, dorsal view of right hind 

wing of C. modica showing wing articulation sclerites. Fig. 5, lateral dissection of C. modica (male). 

PLATE 13.-AduIt internal anatomy. 

Figs. 1-4, C. modica: (1) front view or cerebral and sub-oesophageal ganglia; (2) digestive 

system; (3) lateral view of cerebral and sub-oesophageal ganglia; (4) frontal ganglion dorsally. 

PLATE 14.---Adult internal anatomy. 

Figs. 1, 2, C. nl0dica: (1) the nerve chain; (2) corpora allata. 

PLATE 15.--Adult internal anato111y. 

Fig. 1, dorsal view of oesophageal sylnpathetic nervous system of C. rnodica. Fig. 2, corpora 

allata of A. latifascia. Figs. 3, 4, digestive system: (3) T. vo/da; (4) A. latlfascia. Figs. 5, 6, male reproductive 

systeln: (5) A. latifascia; (6) T. volda. Fig. 7) corpora allata of T. vo/da. 

PLATE 16.--Adult internal anatomy (Figs. ]-5). Larval internal anatomy (Fig. 6). 

Fig. 1, female reproductive system of T. volda. Fig. 2, female reproductive system of A. latzfascia. 

Figs. 3-5, C. n1odica: (3) corpora allata laterally; (4) fernale reproductive systeln; (5) male reproductive 

system. Fig. 6, lateral aspect of alimentary canal of A. latlfascia.


3 

5 

1--- 1~4 

'2 

13 

/8 

14 

/5 

19 

PLATE 1


---~__ n 

-----0 2 

I m.m. I 

4 

10-5 mm. 

-.\-,---.--lr------g 

10 

7 

A--- - f 

Jr------------j 

JIIlffT-'~-------~-h 

13 

14~ 

15 

PLATE 2

THREE SPECIES OF CADDIS FLIES (TRICHOPTERA) 

31 

3 

I m.mo i 

m 

5 

-------------------·-----------n 

__s 

(2 

(;3 

--x 

'I 

\ 

I 

12 

Q 

10 

8 

Q' 

__d 

@ 

1 

13 

PLATE 3


ye--I 

) 

4 

.'r- 

.__._-----O ' 

____ J 

---9 , 

--_··_-----~----_··_···_----P-\-.p 

--r~- --~~Y' 

-- --" 

w· 

--------_.,---p 

.- v' 

PLATE 4


'--g 

I 

"'-""--i+'---c 

,...----+---d' 

'J"'---"Ir---/l' 

y;::-;-:-----""'"---c 

J«----f-----h I 

r--r---__)(I 

'-T'-------c 

'1//lJr-~_-----CJ 

----h 

£..--1------9 

------x' 

6 

t mm 

I 

PLATE 5


n--~---~g 

....,.....-'.dr--_d 

c 

4 

) 

r-\ 

4 

-- \ 

( \~ 

5 

6 ) 

6 

--)C, 

7 

7 

s 

PLATE 6

THREE SPECIES OF CADDIS FLIES (TRICHOPTERA) 3S 

...r--.------I 

---_._] 

r-r--~----_k 

5 

6 

9 

10 I---~ 

11 

-u 

-1 

_Cl 

m\l ~ 

IS 

q 

/8 

t----.~r:.r~ 

PLATE 7


9 

w' 

10 

......,......:+-..I--_.~__CO)(O 

I .. ;...r-+-----+'-:'+04-- ffillrOO 

--I-'+-Il----CO)(O 

m£ron 

12 

Jmrn.j 

PLATE 8

THREE SPECIES OF CADDIS FLIES 

(TRICHOPTERA) 

37 

" 2 

'y-------------d 

- \ 

___----c 

In..-·-----~~~IIi"'"r"':~---~=:;:::IIl--r;:__--- f" 

-t--. +-- gll 

{/--~--------- __:IIo~---_+_---h


, J_mm ... 

1 

loom 

Q 

D 

r-~: 

IS 

16 

18 

/9 

~-=----_·--co)(a 

17 

PLATE 10

THREE SPECIES OF CAOOIS FLIES tTRICHOPTERA) 

39 

_~__~v.M'----COXa 

,~~. mqro(\ 

L 

......~--CJ 

VI 

..............--w' 

to 

IS 

16~ 

PLATE 11

40 

KATHERINE KORBOOT 

re 

---0:::------ -. _~A.~ 

ClI NI M 

1


0--------\ 

( 

~J 

.. 

"..........,r-------Q 

I. 

;.- r-h 

._---j =:=T' 

y --------- ----- -- -~-~ 

c' --'---. . _ 

o ---------------- 

2 

__n 

r--··---' 

c'------ 

J 

.' " ,~ 

,. i 

X' 

,- ,. I"".' ~~ I.' .;.,.~ 

-----'---'''1 ' 

d'----------- 

e'--,------ 

f'.--------.----.- ----- 

q"-------------- . 

g' ----- ----- ~-- 

x --------~--- 

PLATE 13


I. 

, - -_. r- 

~' - -- 

r'~----- 

_ 

2. 

q'.- 

t'···_- 

I 

V 

PLATE 14


x-- \) 

1'- ~.~,,~ .. ,~ ... _- ... \ 

1-------0 

.--------b 

-r-n-------c 

~...-----~ 

~-----b 

I 

('-------0 

d'~----------t-.." 

p-----------...zI 

t'-~-~ 

T------g 

I. 

:':-i'J'------- \ 

-------h 

.'iJ---+----f---k 

1----------1 

·n--------m 

~'r_----rn 

""- 

'-'I.'---------n 

-+----+---+------1· 

-+_~ 

bll 

u 

------d 

It 

-;------C 

+---- 0 

I( 

It 

---0 

~----(l 

PLATE 15

44 KATHERJNE KORBOOT 

gll 91\ 

I1 

Y 

hit 

t 

III 

t'* 

kW 

,. 

kIf 

tIt 

I' ,. 

.. 11 

I. 

nU 

Oil m· 

ft· 

tit 

1" 

OH 

3 

Q 

d 

a 

9 

h 

k l 

(' 

.__~_-----

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