412 



INSECT ARCHITECTURE. 



are scarcely perceptible before the beginning or dur- 

 ing the course of the winter. 



It is commonly upon young cattle, such, namely, 

 as are two or three years old, that the greatest num- 

 ber of bumps is found ; it being rare to observe them 

 upon very old animals. The fly seems to be well 

 aware that such skins will not oppose too much re- 

 sistance, and seems to know, also, that tender flesh 

 is the most proper for supplying good nourishment 

 to its progeny. " And why," asks Reaumur, " should 

 not the instinct which conducts it to confine its eggs 

 to the flesh of certain species only, lead it to prefer 

 the flesh of animals of the same species which is most 

 preferable ? " The number of bumps which are found 

 upon a beast is equal to the number of eggs which 

 have been deposited in its flesh ; or, to speak more 

 correctly, to the number of eggs which have suc- 

 ceeded, for apparently all are not fertile ; but this 

 number is very different upon different cattle. Upon 



Bumps or umrblea produced on oattU by the <)x-hrcc;c-jhj. 



