THE GAD-FLIES OR HORSE-FLIES 



(Family Tabanidce.) 



The insects of this important family are known as gad-flies, 

 horse-flies or deer-flies. To this group belong the active, strong- 

 flying creatures which annoy horses to such an extent when one 

 is driving along a wooded road, especially in pine woods, and 

 also the smaller yellowish or greenish flies which annoy forest 

 animals, and which bite human beings when in the woods. The 

 proboscis of all of the flies of this family is in the female sex 

 adapted for piercing and sucking, the males, as in all of the blood- 

 sucking flies, including the mosquitoes, being harmless, and the 

 proboscis not adapted for piercing the skin of mammals. The 

 bites do not ap- 

 pear to be as 

 painful as those 

 of mosquitoes or 

 of black flies, 

 and apparently 

 no poison is in- 

 jected, but any 

 one of these flies 

 may be responsi- 

 ble for the trans- 

 fer of the bacillus 

 of anthrax or 

 "malignant pus- 

 tule," as it is 

 called. The 



adults are great 

 water drinkers, 



and are usually most abundant in the vicinity of inland ponds 

 and streams. This has suggested to Porchinsky, the Russian 

 entomologist, the desirability of coating such ponds with kerosene, 



1.31 



Fig. 74. — Chrysops fugax. (After Osborn.) 



