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 muscids (superfamily 

 Muscina) and the house-fly is the 

 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 



FIG. 37 1 . The ox bot-fly (Hypoderma 

 lineata] 



(After Marlatt, United States Department 

 of Agriculture) 



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

 egg attached to hair at right. (Much enlarged) 



(After Lugger) 



