562 



HOWARD 



they cause great suffering and even death. Several species of 

 this group are referred to in the Hterature of Myiasis. 



Fig. 17. Coinpsomyia ma- 

 cellaria — enlarged ( original ) . 



Chj'ysomyia (^Comfsoinyia) niacellaj'ia Fabr. 



This insect, popularly known as the ' screw-worm fly,' is a 

 famous species in the West. It is one of the most important of 



the insects which affect domestic ani- 

 mals and occurs throughout Central 

 and South America, as well as in the 

 United States. Its greatest damage 

 to domestic animals is done in Texas. 

 The fly lays its eggs on any spot 

 where the skin has been injured, 

 either from a scratch by a barbed- 

 wire fence or the puncture of a thorn. 

 A raw or slightly blood}^ surface at- 

 tracts the flies which lay their eggs 

 and the larvae live in the flesh, mak- 

 ing a large sore. The fly does not 

 confine its attacks to domestic animals, but also frequently at- 

 tacks man. The most common of such cases is where the fly 

 has laid its eggs in the nostrils of some person, usually some 

 one who is troubled with offensive catarrh. The eggs hatch 

 and the larvae work their way through the upper nostrils and 

 destroy the tissues. The soft palate is frequently entirely de- 

 stroyed. Fatal cases in men are not rare. The remedy is to 

 syringe out the nasal passages with dilute carbolic acid. It also 

 feeds in the larval state on dead flesh. Its puparia were found 

 by Dr. Hotter in his investigations on Grave Fauna and the 

 same observer reared this species from larvae found feeding on 

 an exposed human corpse. 



In the present connection, the screw-worm flv has been, on 

 several occasions, captured on human excrement, although it is 

 not an especially common species near Washington. It has 

 been captured on human excrement in Washington, D. C, and 

 at Cabin John Bridge, Maryland, and was also taken at Snickers 

 Gap, Virginia, in an out-of-door privy. 



