Gastricola. Bot-Flies of Solipeds and Reindeer. 6g 



except, absent from dorsal centre on eighth and ninth, and from all but the 

 venter on the tenth, hibernates on duodenal mucosa, passes 30 days as 

 nympha. CE. Flavipes : Yellow, legged bot fly. Distribution: Spain 

 Dalmatia, Africa, Asia Minor, etc. Attacks ass. 



The CEstridse are important in this that their larvae live in the 

 bodies of animals, through the winter, and emerge in spring and 

 develop through the pupa into the perfect fly. The family has 

 the following general characters : 



Head large, and hemispherical ; eyes facetted ; forehead broad 

 with three eyelets ; antennae short ; probo.scis very small or 

 absent ; body usually hairy ; thorax large, prominent ; abdomen 

 has six rings, the male having a rounded caudal end, and the 

 female a very extensible ovipositor which curves forward beneath 

 the abdomen. Viviparous or oviparous. The larva has 12 

 segments, the first two often seeming to coalesce. Between these 

 are two respiratory pores (stigmata), and two more are found in 

 the last segment. The cephalic segment has two strong hooks, 

 which may disappear with growth. Anus beneath the stigmata 

 of the last ring. The larva undergoes two moultings. 



Escaping from its host, the larva burrows in the soil, is trans- 

 formed into the nympha and in three to eight weeks (longer in 

 cold weather) emerges as the perfect fly. 



The mature Jly has the month atrophied, and takes no food, 

 but lives upon accumulated fat, and devotes its whole energy to 

 the reproduction of its species. They have been divided into 

 three genera : Gastricola or gastrophili, living in the alimen- 

 tary canal ; Cavicola living in the nasal sinuses or caverns ; and 

 Cuticola or Hypoderma living beneath the skin and between 

 the muscles. 



GASTRICOI.A. BOT-FI,IES OF SOIvIPEDS AND REIN- 

 DEER. 



ist. CEstrus Equi. (^Gastrus Equi. Gastrophilus Equi) is 

 the largest bot-fly of the horse : length 6 to 7 lines. The body 

 is hairy, yellowish brown with black, white, or yellow spots, the 

 abdomen has a reddish tinge spotted with black. The wing has 

 near its middle a transverse black band, and black spots at its 

 extremity. 



