DEVELOPMENT OF CYNIPID IYPERPARASITES 465 
the ventral side of the Aphidius at either extremity of the 
body. The chitinized larva, and subsequently its cast skin, 
are found in the same position, and orientated indifferently 
in any direction, but the later stages invariably he along the 
dorsal side of the gut of the host with the head towards the head 
of the latter. Hence at some intermediate stage the hyper- 
parasite must change its position. - How this takes place 
was not observed, but, in view of the fact that the cauda of 
analogous forms is sometimes regarded as locomotory, it may 
be remarked that in Charips the first tailed larva does not 
move at all, while at some later stage, when the cauda is 
reduced, a definite, and frequently elaborate, change of position 
occurs. 
THE Funtt-crown Larva (Text-fig. 9). 
When the larva is full grown it makes its way out behind 
the head of the host, whose remains it devours within the next 
few hours. The gut may then be evacuated and metamor- 
phosis ensue speedily, but frequently there is a resting period 
of several days. Thus, in one case, eleven days elapsed between 
emergence and transformation, and in another case, eight. 
The full-grown larva is an apodous form measuring 1-70 x 
0-90 mm. ‘The body of thirteen distinct segments tapers some- 
what to the anus. The skin is smooth, and there are no 
appendages except to the mouth parts. The crescentic labrum 
is furnished with eight small papillae. The mandibles are 
large, bidentate, and strongly chitinized. Hach maxilla bears 
a disk, upon which are three papillae, one of which terminates 
in a short seta; and the labium, which is large and oval, bears 
laterally two pairs of papillae (‘Text-fig. 10). 
The salivary glands, which in this form never secrete silk, 
extend forward from the seventh segment on either side of 
the gut ventrally. Hach gland is a long straight tube composed 
of polyhedral cells, and, in the first segment, enters a duct 
which immediately behind the head unites with its fellow of the 
opposite side to form the short dilated common salivary duct 
