Savory - Arachnida 1977

52 II. DE ARACHNID IS
6. ONTOGENY: GROWTH 53
RO.\CUS LUBRICUS
Adult
Protonymph Deutonymph Tritonymph l\hle Female
CHELICERA
:\lovable 0 I I I I
Fixed 4 5 6 6 6
CARAPACE
Anterior 4 4 4-5 4 4
Ocular 4 4 5-7 5-6 5-7
Median 6 8 78 8 7-8
Posterior 4 6 6 6 6
(I)
(,;)
(Ill)
J1ICROCREAGRIS CA JtBRIDGEl
Adult
Protonymph Deutonymph Tritonymph Male Female
CHELICERA
Movable 0 I I 1 I
Fixed 4 5 6 6 6
CARAPACE
Anterior 4 4 4 4-5 4
Ocular 4 4 4 4 4
.VIedian 4 6 6 6-7 6
Posterior 4 6 6 6-7 6
Young harvestmen are feeble little creatures, which stagger about on
their long legs in a most unimpressive manner. The tarsi have fewer
articulations than in the adult state: thus, recently hatched Oligolophus
has eight, 18, eight and eight pieces to the tarsi of its four legs compared
vvith the 26 to 50 of the adult. A more remarkable contrast is found in
the chelicerae. In the adult the forceps are smooth or nearly so, but in
the very young they are conspicuously or even strongly toothed (Fig.
20), as if this additional armature were a compensation for small size
and bodily weakness.
A newly-hatched solifuge 21) is an immobile and incomplete
creature, existing in a quasi-larval condition until its first ecdysis
changes it into a protonymph. This has a smooth carapace, on which two
transverse furrows foreshadow its later division; and by comparison
with an adult its opisthosoma is also to be described as smooth, fer it
carries but six or ten of dorsal setae. The movable finger of the
chelicera has a small egg-tooth; the pedipalpi and first legs arc directed
backward, lying across the other legs. All legs arc smooth, their seg-
Fm. 20. Chelicerae of
young harvestmen. (i) Phalangium; (ii) Homalenotus;
Mitopus; Oligolophus.
ments ill-defined or invisible. Claws are present, and a very remarkable
racket-organ is situated behind the first and second legs. There are
various, small, external differences between the "larvae" of Galeodes
and Solpuga, but internally they agree in having a blindly ending
alimentary canal, in which there metabolizes a mass of yolk, providing
both energy and material in the apparent absence of functioning respiratory
and ex