368 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
10. The BLACI LOCU8T MIDGK. 
Cecidomyia pseudacacio' Fitch. 
Order Dipteka; family Cecidomyiid k. 
In July and August, the tender young leaflets near the tip of the stem folded 
togt-tlier like a little pod, the cavity inside containing from one to three small milk- 
white maggots, which descend below the surface of the ground, remaining there in the 
pupa state about ten days, and then appearing as a small blackish midge. (Fitch.) 
According to Fitch, before the small young leaflets, which put forth 
along the opposite sides of the main leaf-stalks at their tips, become 
expanded, they are closed together like two leaves of a book ; and it is 
probably at this time that the female midge inserts her e^ in the cleft 
between them, the irritation from which and from the small maggots 
which hatch from them, keeps the leaflet permaneLtly closed; a slight 
cavity forming within, iu which the worms reside, the leaflet hereby 
comes to resemble in its shape a small bivalve shell with a more or less 
wavy edge. The surface remains unchanged outside, but within it 
assumes a pale greenish yellow color. The attachments of the leaflets 
to the stalk becomes so weakened when infested by these worms that 
probably they are generally broken off by the wind, and the worms are 
thus carried to the ground, instead of crawling down the stalks by 
night, as is the habit of the wheat midge. 
The female. — A small blackish midge, the base of its thorax tawny yellow, its 
abdomen pale yellowish, with the tip dusky and clothed with fine hairs, as is also 
the neck ; its legs black, with the thighs pale except at their tips; its wings dusky, 
feebly hyaline, with the fringe short; its antennae with thirteen short cylindrical 
joints separated by short pedicels ; its length, 0.065 inch to the tip of the body. 
17. The yellow locust midge. 
Cecidomyia robin ia? Haldemau. 
Order Diptera; family Cecidomyiid.k. 
In July and August a portion of the edges of the leaves rolled inwards on their 
under sides and thickened, inclosing one or two very small white maggots, which 
are varied more or less with orange-yellow ; producing a pale orange midge with the 
sides of its thorax and often three oval stripes on the back and the wings dusky; 
its antenna? blackish and of fourteen joints in the females, twenty-four iu the males; 
its length, 0.12 inch. (Fitch and Haldemau.) 
Professor Haldemau, who described this two-winged gall-fly in Em- 
inon's Journal of Agriculture and Science, October, 1847, says that it 
in conjunction with the Hispa, already mentioned, had been so numer- 
ous in southeastern Pennsylvania the two preceding summers as to kill 
the leaves upon the locusts, the trees in August appearing as though 
they had been destroyed by dry weather. 
This insect may be detected by the margin of the leaflets being rolled 
inwards upon their under sides for a length varying from over a quar- 
ter to a half inch, the upper side showing a concavity or rounded hollow 
at this point. "This rolled portion," says Fitch, "is changed in its 
