THE BLACK FLIES AND BUFFALO GNATS 



(Family Simuliida.) 



These insects, known as black flies, sand flies or buffalo gnats, 

 are small, stout, hump-backed, biting flies with broad wings and 

 rather short legs which are sometimes speckled, and with short, 

 straight, simple antennae. The eyes of the male are very large 



and frequently touch each other, 

 and the insect in this sex does 

 not bite. The family contains 

 only the single genus Simulium 

 of which the black flies of the 

 north woods and the buffalo 

 gnat of the Mississippi and 

 Missouri valleys are well known 

 examples. They rival the mos- 

 quito in their blood-thirsty ten- 

 dencies and not only do they 

 attack human-beings, but poul- 

 try and domestic animals are 

 frequently killed by them. 

 There is one case on record in 

 which a man was killed by in- 

 numerable bites. In certain 

 seasons they multiply enor- 

 mously, alight in thousands 

 on cattle and produce death 

 through their poisonous bites as well as from loss of blood. Un- 

 like mosquitoes they fly and bite in the day time and are often 

 seen in large numbers flying in bright sunshine. The larvae are 

 aquatic and unlike mosquitoes again, the larvae of which live in 

 stagnant water, Simulium larvae frequent well aerated and fre- 

 quently swiftly running streams. They are found most abundantly 

 on rocks or logs so near the surface as to cause a rapid ripple. 



Fig. 69. Simulium meridionale. 

 (From U. S. Dept: Agr.) 



120 



