140 POPULAR ENTOMOLOGY. 



where the larvae attain their full size, and even assume the 

 pupa state, in which form they are deposited by the parent ; 

 this egg-like cocoon is at first soft and white, but soon 

 hardens, becomes brown and of a round shape. These 

 curious particulars were discovered by Reaumur, who, being 

 anxious to observe the hatching of these singular eggs, as 

 he thought them, carried some in his pocket by day, and 

 took them to bed with him at night, that they might have 

 the proper warmth ; his surprise was great, when, instead of 

 grubs, perfect Plies were produced. Mr. Curtis observes 

 that " these flies move swiftly, and, like a crab, sideways or 

 backwards, and that they are very tenacious of life." It is 

 also remarked by Latreille that the ass fears them the most, 

 but that they cannot cause much pain, or horses could not 

 live in forests in the summer. 



