416 INSECT ARCHITECTURE. 



caused by the ox breeze-fly. It requires six months 

 to come to maturity, and if it is irritated it eats 

 deeper into the flesh, sometimes causing fatal inflam- 

 mations. 



Grub Parasite in the SxVail. 



During the summer of 1829, we discovered in the 

 hole of a garden-post, at Blackheath, one of the 

 larger grey snail shells {Htlix aspersa^ Muller), 

 with three white soft-bodied grubs, burrowing in the 

 body of the snail. They evidently, from their appear- 

 ance, belonged to some species of beetle, and we 

 carefully preserved them in order to watch their 

 economy. It appeared to us that they had attacked 

 the snail in its strong hold, while it was laid up tor- 

 pid for the winter; tor more than half of the body 

 was already devoured. They constructed for them- 

 selves little cells attached to the inside of the shell 

 and composed of a sort of fibrous matter, having no 

 distant resemblance to shag tobacco, both in Ibrm 

 and smell, and which could be nothing else than the 

 remains of the snail's body. Soon after we took 

 them, appearing to have devoured all that remained 

 of the poor snail, we furnished them with another, 

 which they devoured in the same manner. They 

 formed a cocoon of the same fibrous materials during 

 the autumn, and in the end of October appeared in 

 their perfect form, turning out to be the JDr'ihis jla- 

 vescens the grub of which was first discovered in 

 France in 1824. The time of their appearance, it 

 may be remarked, coincides with the period when 

 snails become torpid.* 



^ J. R. 



