234 



ELEMENTARY ENTOMOLOGY 



whose maggots work in the nasal sinuses of sheep, causing " grub- 

 in-the-head," which often results in fatal vertigo, or 'staggers." 



Other species affect various wild 

 mammals, one inhabiting rabbits 

 being particularly common in the 

 South. When full grown, the bots 

 pass out with the excreta, or drop 

 to the ground, in which they 

 pupate. 



The muscids. The last group 

 of the typical flies is much the 

 largest and is now held by most 

 students of this order to represent 

 from twenty to thirty families, so 

 that it may be considered as a 

 superfamily. They are all com- 

 monly called muse-ids (superfamily 

 Muscina) and the house-fly is the 



(After Marlatt, Umte^d States Department best . known example. No attempt 



will be made to give the technical 



distinctions by which the different families or subfamilies may be 

 distinguished, for the knowledge of an expert is required for their 

 recognition ; but the different groups will be considered according 



FlG. 371. The ox bot-fly (HypoJerma 

 lineata] 



FIG. 372. The horse bot-fly (Gastrophilus eq2ti], male; abdomen of female at left ; 

 egg attached to hair at right. (Much enlarged) 



(After Lugger) 



