D54 MODERN CLASSIFICATION OF INSECTS. 
The neuration of the wings, which in other groups of Hymenoptera 
is of essential importance in generic distribution, here becomes of 
minor consideration, from the little variation in this character; hence 
the arrangement of Jurine, founded thereon, is very imperfect. 
The larva feed exclusively upon pollen or honey. Some of the 
species live in society, residing in dwellings of a beautiful construction, 
the work of the females and neuters, or of the latter alone ; the larvee 
being in such cases separately enclosed in hexagonal cells, and at- 
tended and supplied with food by the females and neuters: others, 
however, are solitary in their habits, without any neuters ; the females 
building nests, generally composed of a series of cylindrical cells, for 
the reception both of the eggs and a supply of pollen paste sufficient 
for the support of the grubs when hatched, a single larva occupying 
each cell: others, again, are solitary, but do not build nests, de- 
positing their eggs, cuckoo-like, in the already provisioned cells of 
other bees; so that, when the progeny of the latter are hatched, they 
are either starved to death in consequence of the grub of the former 
devouring all the provisions (being most probably first hatched), or 
are even perhaps devoured by the former.* The perfect insects feed 
only upon the nectar of flowers. 
The larva in this section is a whitish, short, thick, and fleshy grub or 
maggot, having a wrinkled body, somewhat pointed at each end, and 
generally observed in a curved position (jig. 90. 9. larva of Colletes ; 
91.15. ditto of Anthidium). It is entirely destitute of feet. The head 
(jig. 90. 10. head of larva of Colletes seen in front; 11. sideways; 91. 
16. head of larva of Anthidium seen in front, 91.17. ditto sideways. ) 
is small, and placed low upon the first segment of the body; it is 
smooth on the upper part, having a minute conical tubercle on each 
side, which seems to be articulated near the base and tip (fig. 91. 18.). 
Those two parts were considered by Swammerdam and Walckenaer as 
the rudimental eyes of the perfect insect; but from their structure it is 
evident that they must rather represent the antenne. Below these is 
to be observed a small transverse lip, answering to the upper lip of the 
perfect insect ; and below this is a pair of horny jaws (fig. 91. 16, 17. 
md), small, having a transverse movement, and shutting under the 
* The latter opinion has need of confirmation. In the burrowing Fossores, the 
parasites doubtless devour the larve of the founder of the nest, the latter being also 
carnivorous ; but as the larve of the working bees are pollinivorous, it is contrary to 
analogy that their parasites should be otherwise than pollinivorous. 
