272 



ORDER DIPTERA 



skin and some time before it is ready to issue. The adults 

 appear quite early in the season and the larvae in the hacks 

 of cattle are never seen until in the winter time — January 

 first to March or April. They cause the muscles to have a 

 jelly-like consistency. They injure the cattle in regard to 

 growth and to milk conditions. The annoyance of the flies 



^ \ 4 ' 







Fig. 217. — Hypoderma lincata: a, eggs attached to hair; b, c, d, dorsal, 

 ventral, and lateral view of egg; e, embryonic or first larva, as seen in egg; 

 /, a, mouth parts of same enlarged; h, anal segments of same'still more 

 enlarged. (From Insect Life.) 



when they deposit eggs and also the injury caused by their 

 presence in the back of the cattle is in England estimated 

 at about -15.00 a head. Eggs are attached to the hairs, and 

 the larvae, according to Curtice, pass into the mouth and 

 through the esophagus and through its walls into the adja- 

 cent tissue and migrate by slow degrees to the dorsal portion 

 of the body, finally reaching the subcutaneous tissue along 



