296 MODERN CLASSIFICATION OF INSECTS. 
just large enough to admit it. All this time the wasp is active, and 
associates with its companions. When just protruded, the head of 
the larva is of a pale brownish colour, but by degrees it assumes a 
rounder form, and becomes almost black. 
On endeavouring to remove one of these full-grown larvee, the 
head of which was exserted, I found it impossible to detach it, 
although I had widened the space where the head protruded, the 
neck being apparently in some manner attached to the interior surface 
of the bee’s abdomen. After much difficulty, I ascertained that this 
attachment was caused by a fine thread extending from one side of 
the neck, and firmly attached to the abdomen ( fig. 93.15.) of the bee.* 
Whether this thread was tubular or not, I cannot state; but the cir- 
cumstance, combined with the want of manducatory organs in the 
head of the Stylops larva, as noticed by Jurine, seems to favour the 
opinion originally entertained by Mr. Kirby, that the Stylops, in its 
larva state, feeds by absorption. I would, however, by no means wish 
it to be considered that this view of the subject is satisfactorily esta- 
blished, even although it appears to be confirmed by the examination 
of the exuvia of a Stylops larva remaining within the abdomen of a 
bee after the perfect Stylops had escaped. This, on removal, was 
found to consist of a thin and transparent pellicle (fig. 93. 14.), being 
of a long, cylindrical, and narrowed form, having the dorsal portion more 
darkly shaded, and presenting the appearance of indistinct articulations. 
This, therefore, was undoubtedly the larva-skin of the insect: the 
neck exhibited the thickened appearance visible in the neck of the 
larva, and precisely in the same situation that the thread above 
noticed was attached in the larva, I observed an apparent spiracle 
or circular aperture connected with an incrassated and apparently 
tubular process of the neck. Within the pellicle I likewise observed 
a long thread, which appeared to arise from the same aperture; but 
this might possibly be accidental, as it was removed without any 
difficulty or rupture. 
* Mr. Newman ( Mag. Nat. Hist. No. 23.), after making the observation quoted 
above (p. 147. note $), questions whether Stylops may not feed in a similar manner. 
L. Dufour (Ann. Sci. Nat, Jan. 1837, p. 16.) describes a larva, probably of a 
Stylops, found in Andrena aterrima, and attached upon one of the large trachean 
vesicles, which occupy the base of the abdominal cavity of this bee, by means of 
two trachean trunks, which entered the body of the larva near the anterior extre- 
mity, whereby it obtained a supply of air in a manner quite anomalous. 
