THE AMERICAN WHEAT-FLY. 593 
and prominent. Its face and feelers are yellow. Its an- 
tennae are long and blackish. Those of the male are twice 
as long as the body, and consist of twenty-four joints, 
which, excepting the two basal ones, are globular, sur- 
rounded by hairs, and connected by slender portions, like 
heads on a string.* The antennae of the females are about 
as long as the body, and consist of only twelve joints, 
which, except two at the base, are oblong oval, narrowed 
somewhat in the middle, and surrounded by two whorls 
of hairs. These insects vary much in size. The largest 
females do not exceed one tenth of an inch in length; 
and many are found, towards the end of the season, less 
than half this length. The males are usually rather smaller 
than the females, and somewhat paler in color. Among 
hundreds that I have examined in the living state, I have 
never found one specimen with spotted wings. 
The time of their appearance in the winged form varies 
according to the season and the situation, from the beginning 
of June to the end of August. In Salisbury, Connecticut, 
they had entirely disappeared before the 25th of July, 1851 ; 
but during the same year I found them still in some num- 
bers at North Conway, in New Hampshire, on the 17th of 
August ; and, three days later, near the base of the White 
Mountains. In most parts of New England where wheat 
is cultivated, immense swarms of these orange-colored gnats 
infest fields of grain towards the last of June. While the 
sun shines they conceal themselves among the leaves and 
weeds near the ground. They take wing during the morn- 
ing and evening twilight, and also in cloudy weather, when 
they lay their eggs in the opening flowers of the grain. 
New swarms continue to come forth in succession, till the 
end of July; but Mr. Buel says that the principal deposit 
of eggs is made in the first half of July, when late-sown 
winter-wheat and early-sown spring-wheat are in the blossom 
* These joints seem to me to be somewhat approximated in pairs. 
75 
