LIBRARY

EPHEMERIDA 223
Adults with many fine wing veins, very small hind wings, and three very
long equal caudal filaments. The male claspers are three- or four-segmented,
the basal segment very broad, the second long and incurved, the third short,
and the fourth about half as long as the third. When but three segments are
present, the base is wider and as long as or longer than the second. The third
is only slightly shorter than the second.
This is a large and widely distributed family of which the most important
genera are: Choroterpes Eaton (Holarctic), Thraulus Eaton (HoI arctic, Indo­
Malaysian), Atalophlebia Eaton (Neotropical, Indo-Malaysian), Habrophlebia
Eaton (Holarctic), Leptophlebia Westwood (Holarctic), Adenophlebia Eaton
(Ethiopian), P araleptophlebia Lestage (Palrearctic), and H abroleptoides Schoenemund
(Palrearctic).
Family EPHEMERELLIDJE KlapiHek 1909 (Ephle-mer-eWi-dre, from the
Greek i:cf;hJL€pos, living but a day, + the Latin diminutive ella).
The naiads are elongated or rather short and almost crab-like. They have
rather long antennre and three equal, nearly naked or fringed caudal filaments.
The gills are flat and half or a third the width of the abdomen.
They cling to stones, often to the undersides, in swift waters. In some the
venter of the abdomen forms a sucking disk. They are often strikingly and cryptically
colored.
The adults have very small hind wings and three caudal filaments. The
male claspers are three-segmented, the basal and apical segments short and the
middle segment very long and incurved.
The most important genera are Ephemerella Walsh (Holarctic), Drunella
Needham (Nearctic), Teloganodes Eaton (Indo-Australian), and Torleya Lestage
(Palrearctic).
Superfamily ECDYUROIDEA (HEPTAGENEOIDEA Ulmer 1920)
KEY TO FAMILIES
1. CUI, CUa and lA of fore wing somewhat parallel and equal in length; hind
wing almost circular, with many long intercalary veins; pronotum
very small. . BlETISCIDlE p.225
CUI and Cu. of fore wing close at base but strongly divergent distally;
CUa much shorter and more strongly curved than Cu,; hind wing
oval. . .. . 2
2. CUI of fore wing with more or less oblique, sinuous veinlets passing to
wing margin (SIPHLURIDlE) . . SIPRLONURIDlE p. 224
CUI of fore wing without such veinlets; two or four parallel unattached
intercalary veins in cubital area. 3
3. One pair of intercalary veins between CUI and CUb sometimes vestiges
of a second pair lying near CUa: two or three caudal filaments
AMETROPODIDlE p.224
Two pairs of intercalary veins between CUI and Cu., the larger pair
Ilear Cu,; two caudal filaments (HEPTAGENIIDAE) ,ECDYURIDlE p.224