OZ SIDNEY I. KORNHAUSER 
They are probably some of the katabolic substances formed in 
the parasites’ development which are stored in an insoluble con- 
dition rather than being thrown into the haemolymph of the 
host, as the host might be unable to rid itself of these waste 
products. 
The final molt of the parasitic larvae and their escape from 
the host is the next act. This generally occurs during the fifth 
nymphal instar of Thelia, but if oviposition of the parasite 
occurs late in the ontogeny of the host, the Aphelopus larvae 
reach maturity in the adult Thelia and escape often with some 
difficulty from the imagos. The fact that the parasites may be 
present in adults and are found there in various stages of devel- 
opment makes this paper possible. In Lepidoptera, for instance, 
the larvae or pupae are always destroyed by their polyembryonic 
parasites, and so we cannot tell how the sexual characteristics of 
the imago might have been affected. The Thelia nymph or 
adult from which the larvae are soon to emerge leaves its com- 
rades, climbs to a solitary twig or leaf, and fastens itself firmly 
with its tarsi. Small elevations running in rows across the 
abdominal sterna appear. A little later each elevation becomes 
a hole from which the caudal end of a green or yellowish eruci- 
form larva emerges. Before escaping the larvae devour the 
entire contents of the host, leaving only an empty shell clinging 
to the leaf or twig. By wriggling motions, the larvae work their 
way out of the host and also out of the integument of the mega- 
gnathic stage. The integument is broken in the dorsal region 
behind the circumcephalic plate and the eruciform larva leaves 
its exuvia at the hole through which it emerges from the Thelia. 
The chitinous jaws of the exuviae plainly mark the holes made 
in the sternites of the host (figs. 48 and 47). The eruciform 
larvae (fig. 2) are entirely different in form from the mega- 
gnathic larvae, having small jaws and a very bristly integument 
marked into distinct segments by rings of spines. They are 
yellow or light green, depending upon the amount and color of 
the pigment which was present in the body of the host. On the 
average, thirty-five larvae free themselves simultaneously, the 
abdomen of the host bending until the ventral surface is par- 
