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 

 beads 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 Con way, 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. 

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