454 HABITATIONS OF INSECTS. 



as they originate not from the egg, but from the larva, 

 which, in the operation of extracting the sap, in some 

 way imparts a morbid action to the juices, causing the 

 flower to expand unnaturally : and the same remark 

 is applicable to the gall-like swellings formed by many 

 Aphides, as A. Pistacice, which causes the leaves of 

 different species of Pistacia to expand into red finger- 

 like cavities : A. Pini^ which converts the buds or 

 young shoots of the fir into a very beautiful gall, some- 

 what resembling a fir-cone, or a pine-apple in minia- 

 ture ; and A. Bttrsaricey which with its brood inhabits 

 angular utriculi on the leafstalk of the black poplar, 

 numbers of which I observed this year on those trees 

 by the road-side from Hull to Cottingham. — The ma- 

 jority of galls are what entomologists have denomi- 

 nated monothalamous, or consisting of only one cham- 

 ber or cell ; but some are polythalamous, or consisting 

 of several. 



Having thus described the most remarkable of the 

 habitations constructed by the parent insects for the 

 accommodation of their future young, I proceed to the 

 second kind mentioned, namely, those which are formed 

 by the insect itself for its own use. These may be 

 again subdivided into such as are the work of the in- 

 sects in their larva state ; and such as are formed by 

 perfect insects. 



Many larvae of all orders need no other habitations 

 than the holes which they form in seeking for, or eat- 

 ing, the substances upon which they feed. Of this de- 

 scription are the majority of subterranean larvae, and 

 those which feed on wood, as the Bostrichi, F. or la- 

 byrinth beetles 5 the Anobia, F. which excavate the 



