AQUATIC INSECTS IX NEW YORK STATE 341 



The first species seen and felt occurs early in the spring, soon 

 after the snow disappears. It is a very small species, which flies 

 with great force so that it can be felt when striking the face. 

 It seems that it does not care much for human blood, but it 

 irritates considerably by being of a very inquisitive nature, 

 €ven entering the mouth, nose, ear and what is worse, the eye. 

 If horses are left standing for some time in the roads, they are 

 apt to become restive, shake their heads in a violent manner, 

 frequently stamping and snorting at the same time. If the ears 

 of the horse are inspected, we usually find the cause of their 

 irritation in a large number of such small flies, which are busily 

 ^'ngaged in sucking the blood, and they do so by inserting their 

 powerful piercing organs into a vein, hence they seem to be ar- 

 ranged in regular rows. If not oecuring in very great numbers, 

 they cause but little harm, and an application of a little grease 

 rubbed together with a few drops of carbolic acid, soon reme- 

 dies the evil, and drives away other intruders. This species 

 flies from ilay 15 to June 1, and very likely breeds in the Mis- 

 sissippi river near Minneapolis, though the earlier stages have, 

 as yet, not been found. A little later in the season, but chiefly 

 during June and July, a somewhat larger species (S i in u 1 i u m 

 decorum Walker) becomes numerous. This species occurs 

 sometimes in large numbers, but only females have been found 

 thus far. This is of course easily explained by the fact that 

 only the females of these flies are bloodthirsty; the males re- 

 main near the place of their birth, some running water, and, as 

 they have only a rudimentary mouth, they could not imbibe 

 "blood, even if they were inclined to do so. This fly attacks, by 

 preference, cows, and is sometimes found in such large numbers 

 as to cause some injury to them. They are found most usually 

 in the ears, and between the legs, or wherever the skin of the 

 animal is thin and not well protected with hairs. Sometimes 

 the cows suflier severely from their attacks, and, being con- 

 stantly irritated by these small tormentors, they lose in flesh 

 and give less milk. The front feet are in constant motion, a 

 Tiabit all species have, and are utilized more as feelers than as 

 legs. This species is found active during the whole summer and 

 autumn, but only in certain places, which can however be very 

 far from the breeding places, and these insects must possess 

 some very powerful sense to detect their victims such long dis- 

 tances. 



The damage done in the South is described by Eiley as 



follows: 



As far as can be learned the damage in Louisiana was but 

 slight prior to 1850; but many animals were killed in 1861, 1862, 



