DIPTERA. 475 



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 twenty-fifth of July, 

 1851 ; but during the same year, I found them still in some 

 numbers at North Conway, in New Hampshire, on the seven- 

 teenth 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 morning 

 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 or milk ; and 

 this statement agrees with the observations of Mrs. Gage. 

 The flies are not confined to wheat alone, but deposit in bar- 

 ley, rye, and oats, when these plants are in flower at the time 

 of their appearance. I have found the maggots within the 

 seed-scales of grass, growing near to wheat-fields. The eggs 

 hatch in about eight days after they are laid, when the little 

 yellow maggots or grain-worms may be found within the 



* These joints seem to me to be somewhat approximated in pairs. 



