200 NEW YORK STATE MUSEUM 
Life history. Messrs Russell and Hooker state that the midges 
emerge from the ground from May rst to the 2oth, all disappearing 
by June 1st. May 4, 1908 five adults were captured and by the 
tith the insects occurred in thousands, being so numerous that it 
was only necessary to sweep an open cyanid jar over the top of, and 
through the grass to obtain all the specimens desired. The flies appear 
just as the leaves begin to unfold and, for a time, after emerging, 
large numbers may be found in the early morning and on wet days, 
especially under the tree. As it becomes warmer and the dew dries 
they rise among the branches. The flight is feeble and the insects 
do not fly out beyond the borders of the tree. Oviposition begins 
when the leaves are 1 to 2 inches long, the eggs being deposited for 
the most part upon the under side and irregularly scattered between 
the veins. A few are laid, apparently by accident, upon the upper 
surface. An average of 70 eggs was obtained from each of 50 leaves, 
not over 6 being upon the upper surface, the total number varying 
from 40 to 120. One leaf 12 inches wide bore 28: eggs on its lower 
surface and 175 on the upper. The eggs hatch in from 4 to 6 days, 
the time varying with the weather. The young larvae migrate at 
once to the edge of the leaf or to any hole in it and begin to feed on 
the upper surface. After about 4 days of this feeding the edge 
begins to curl over on the upper surface, forming a roll, the upper 
face of which becomes more or less reddish. The larvae feed within 
this roll, extending it with the growth of the leaf. Occasionally a 
young larva feeds for a time in a circle on the exposed surface of 
the leaf, causing it to become reddish and wrinkled. May 22d 
nearly all the leaves near the ground bore rolls which, in some cases, 
nearly encircled the leaf, while in others they were about one-fourth 
of an inch long. One roll an inch long contained 25 larvae, while 
only a few were present in others. The longer rolls are said to con- 
tain relatively fewer larvae. The larval stage persists through the 
summer, full growth being attained by the last of September or the 
first of October, at which time all except those parasitized enter 
the ground and pupate prior to cold weather. Exceptionally full- 
grown larvae may be unable to escape and winter in the roll, the 
adults appearing at the usual time in the spring. 
Natural enemies. This species is attacked by a chalcid egg para- 
site which appears at the same time in swarms almost as large as 
those of the host. The female chalcid walks around among the 
midge eggs, touching them rapidly with her antennae and stopping 
every now and then to insert her ovipositor and lay an egg in that 
of the host, neglecting others in the immediate vicinity. A mite 
