49 
effect of frost on the flies, but especially to the death of green clover 
heads before any larvae therein can attain their growth. It is possible, 
however, that flies of early September produce larvae capable of sur- 
viving the winter. 
Thus there are in central Illinois two full broods of the seed- 
midge each year and a feeble third generation of flies, which belong 
essentially to the May brood of the next year. In the literature we 
find that maggots of the seed-midge emerged in innnense numbers 
from clover heads in Washington, D. C, on May 23, 1880. This date 
would be one month too early for such an occurrence in this part of 
Illinois, where May 23 is ordinarily the time of maximum abundance 
of the first generation of flies. 
Habits. — The eggs are laid always in green flower-heads, and 
chiefly during the warmer part of the day. . With the aid of a hand 
lens, the process of oviposition can be observed, the female being fre- 
quently too busy to pay any attention to slight interruptions. The last 
four segments of the abdomen of the female are elongate like a tele- 
scope, forming a slender tapering ovipositor, twice as long as the re- 
mainder of the body and as flexible as a whip-lash. Standing on the 
outside of a green clover-head, the female inserts this organ among 
the florets and works it deeper and deeper until it can go no farther. 
The sensitive tip of the sinuous ovipositor finds a suitable spot for an 
egg and the female becomes quiet until the egg is laid. The entire 
process of egg-laying requires usually five minutes, and often ten to 
fifteen minutes. Tho the same female may lay several eggs in one 
clover head, she appears to make it a rule to distribute her eggs among 
a good many plants. Many females may, of course, oviposit in the 
same head, with the result sometimes that more larvae hatch than 
can possibly find food. Thus in one head of eighty florets the writer 
found 106 eggs. Once in a while an egg is laid on a petal or on the 
calyx itself, but almost always it is glued to one of the hairs of the 
immature calyx, the glue often forming quite a perceptible mass. This 
is contrary to a published statement that the eggs "do not appear to 
be glued to the hairs." 
The newly hatched larva has only one way of entering the ovary 
of a flower, namely, by squeezing in between the unopened petals, as 
Comstock said. Once inside the flower-bud, the maggot, incapable of 
biting any solid substance, sucks the fluid contents of the ovary, de- 
stroying the ovule or ovules. An affected floret presents externally 
a healthy appearance but the petals do not expand, except rarely. 
They remain fresh and pink until after the maggot leaves the bud, but 
eventually fade and wither away without opening. 
The simplest way to get specimens of these larvae is to collect 
clover heads that are partly green and partly in bloom, and to shake 
them up a little, when many of the larvae will squirm their way out of 
the buds. The maggots often occur in great numbers on the bed of a 
hay wagon or the floor of a barn. In a tight glass jar of clover heads 
all the larvae present will emerge, and the precise amount of infestation 
can be ascertained. 
