DEVELOPMENT OF CYNIPID HYPERPARASITES 463 
periphery transverse bands of chitin extend into the lumen, 
and give it a spiracle-like appearance. Owing to the opacity 
of the chitinous coat the internal organs cannot be seen, but 
the outline of the gut, which already contains food globules, is 
faintly visible by transparency. 
The larva is curved ventrally with the tail bent round to 
form an angle with the abdomen. Its usual position is between 
the nerve-cord and gut of the host, either in the anterior cr 
posterior third of the body. Owing to the manner in which 
the Aphidius hes in the aphid these are the parts most 
accessible to the ovipositor of the female Charips, and 
thus the earliest larval stage is presumably found where the 
ege has been deposited. The chitinized stage persists for 
a variable time. In one case observed the skin had been cast 
and left behind when the larva emerged from the trophic 
membrane. In others it lasted from two to four days. In the 
later stages the chitin can be found among the host’s tissues. 
In ecdysis the skin usually splits transversely across the thorax, 
and the larva slips out. I have occasionally found examples 
in the second instar in which the moult had been imcom- 
plete, and the body of the larva was still encircled by one or 
more of the chitinous bands, like a rolled napkin enclosed 
by a ring. 
THE Seconp Instar (Text-fig. 7). 
The second instar resembles the first in size and general 
form, but is white and transparent without thickened chitin. 
The mouth is transversely oval, and furnished with two large 
simple mandibles. Below it is a pair of ventro-lateral lobes 
surmounted by sensory papillae. Each of the three first body- 
segments bears a pair of protuberances on the ventral surface, 
and the segmentation of the body is less marked. 
The internal structure is visible through the transparent 
integument. The salivary glands lie latero-ventrally on either 
side of the midgut as two straight tubes. The nerve-cord 
appears as a broad unconstricted band. The two Malpighian 
tubules are very short, and immediately behind their orifices 
