342 DISEASES OF CATTLE. 



the wings ample. These pests are migratory, or are driven in swarms 

 by the wind, hence they appear in localities remote from their breeding 

 place. They have been seen as far north as Jackson County, 111., and 

 Daviess County, Ind. As a rule, however, they are restricted to the 

 counties bordering on the Mississippi Eiver, from St. Louis, Mo., to Eed 

 River in Louisiana. Arkansas appears to be their great breeding place, 

 and nearly the whole State is more or less afflicted with them, especially 

 along the streams and valleys. Occasionally they extend their flight 

 into southeastern Kansas. Overflows of the Mississippi, occurring in 

 March, April and May, are generally soon followed by dense swarms. 

 This pest has been known as far back as the earliest settlements of 

 Kentucky and Tennessee. The appearance of the buffalo gnats occurs 

 each year with the continuous warm weather of spring, when they may 

 be seen to gather in swarms on the vegetation along the confluent 

 streams of the Mississippi, and from thence are drifted about by the 

 winds, and carried sometimes for long distances. At first the members 

 of a swarm are very blood-thirsty, but they soon begin to die off until 

 all have disappeared. The duration of an invasion of the infested region 

 varies from a few days to five or six weeks. Cold weather renders them 

 dormant, until the warmth of the sun revivifies them again, while very 

 hot weather kills them. When these gnats have filled themselves with 

 blood from an animal they soon die. The females alone leave their 

 breeding place, the males always remain. In their migration they select 

 certain places, generally low and wet ground; exposed sunny spots are 

 shunned. Some years they prove very disastrous to the stockowners in 

 the infested regions, and as they do not appear each year in the same 

 place they often swarm in upon a wooded pasture, or attack cattle pass- 

 ing along the road, which become worn out from the attack before 

 they can be brought to a safe place. They are most active in the early 

 morning and evening, exceedingly quick in their movements, and almost 

 noiseless. When they are very numerous they cover the whole animal 

 without regard to position; thus when cattle are weakened from ex- 

 posure during winter, and by scarcity of feed, they succumb easily. 

 When cattle are attacked they attempt to run away from them, and 

 generally aim to reach brushwood or thickets in order to rub off their 

 tormentors. If near water they plunge into that, and remain in it until 

 the gnats leave the place, or the animal becomes pinched with hunger. 

 Animals which have a smooth, short coat are not so badly punished as 

 those with long hair. The bites of a few gnats will not affect the animal 

 seriously, but when attacked by swarms they rapidly weaken from loss 

 of blood and shock, and may die subsequently from exhaustion or blood 

 poisoning. The fatality is much greater among mules than cattle. 

 Their mode of attack is to follow the hair to the skin, plunge their stout 

 beaks into it, and fill themselves with blood; they then drop off, and 

 die within twenty-four hours. The place of puncture on the animal is 

 marked by a drop of blood which oozes from the wound. Their breed- 



