210 



BOT-FLIES. 



in the soil, and in the winged or adult form they fly about in 

 search of quadrupeds upon which to deposit their eggs. In 

 this winged state the flies are very active only during the 

 warmer portion of the day and delight to bask in the sun, 

 sitting upon some elevated rock or dead tree. Many species 

 of Bot- or Gad-flies are known, each living,as a general rule, 

 in its larval state in some particular animal, and usually 

 even in a certain organ of that host. Man is not exempt, 

 and in tropical America tumors caused bA^ one or more spe- 

 cies of such parasites are not uncommon. Even in more 

 temperate regions such larvae are found from time to time 

 under the skin of man. Fig. 174 shows a larva of the Bot-fly 



of man{Dr/'/natohia noxiaJix Goudot) 

 taken from man. Dr. John Hamil- 

 ton describes in the Entomological 

 News a case that came under his 

 observation. He writes: 



"Several years ago I saw, pro- 

 fessionally, a boy six years of age 

 who had been suffering for some 

 months from the glands on one 

 side of his neck being swollen and a 

 fetid ulceration around the back 

 teeth of the lower jaw of the same 

 side. Three months treatment 

 was of no avail, and the end 

 seemed near; one day a white object which was seen to move, 

 was observed in the ulcer at the root of the tongue, which 

 on being carefully extracted proved to be a large grub, 

 wdiich, from having frequently seen them, I recognized as a 

 full-grown larva of Hypoderma. It was of the usual tawny 

 color, about half an inch long when contracted, about one- 

 third that thickness, and quite lively. The case ended fatally. 

 This boy had been on a farm in Illinois the previous fall, 

 where probably the egg^ was in some way taken into his 

 mouth, and the larva found between the base of the tongue 

 and the jaw suitable tissue in which to develop, coming to 

 maturity at the same time with those bred in cattle: 



Bot-flies are stout and hairy insects, usually resembling 



Fig. 174. — Bot-fly of mau. 

 Enlarged. Alter Brauer. 



