180 
PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
Sometimes, and apparently usually, the end of this stalk passed 
through the shell of the egg as well as through the body of the cater- 
pillar, as indicated in the figures (fig. 19, PI. XI, fig. 3). When the egg 
hatches, the larva does not entirely leave the shell, but remains with 
its anal end thrust into it, and the stalk, 
which is hollow, becomes functional and acts 
like a lifeline attached to a submarine diver 
in supplying a connection with the outer air. 
As the larva grows the stalk increases in thick- 
ness, and the last anal segment of the larva 
becomes covered with a thick chitinized shield, 
which is unaffected by the action of strong 
caustic potash. There are two larval molts, 
and consequently three larval stages. During 
the entire course of both the first and second 
the young parasite remains quite firmly at- 
tached to its anal shield and lifeline and the 
cast skins are not entirely sloughed off, but 
are merely pushed backward. After the third 
ecdysis it retains this connection for awhile, 
and grows rapidly, but about the time when 
it reaches maturity the connection with the 
shield is broken, thus proving that it is not part and parcel of the 
integument. It would appear rather that this shield, including a tube 
within the egg-stalk (which, as stated, grows in thickness after the 
egg itself hatches), is actually part of the integument 
of the first-stage larva, and that the second and third 
stages merely continue to use what is in effect the skin 
of the first larval molt. 
The host caterpillar is completely destroyed except 
for the harder chitinous parts, head, tarsal claws, hooks 
of the prolegs, etc., and the hair, which is left in a sort 
of hank, more or less completely surrounding and con- 
cealing the parasite larva. It is impossible to distin- 
guish between the larvae of Schedius and those of its 
secondaries from an external examination of the eggs. 
After the larva reaches its full growth and casts off 
its anal shield, it quickly pupates (fig. 20) and very 
shortly thereafter issues as an adult. There is no indication of a 
desire to hibernate during any part of the preliminary stages, in 
which respect Schedius differs from nearly every other chalcidid which 
has been studied at the laboratory. 
Fig. 19— Schedius Tcuvanx: 
Third-stage larva still retaining 
attachment to egg-stalk, and 
anal shield. Greatly enlarged. 
(Original.) 
Fig. 20. — Scfu diue 
kuvahx: Pupa. 
Greatly en- 
larged. (Origi- 
nal.) 
