AQUATIC INSECTS IN 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, 
even 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 
engaged 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 occuring in very great numbers, 
hey 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 May 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 (Simulium 
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 suffer 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 
habit 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 Riley 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, 
