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cated the point where the female beetle inserted the egg which pro- 
(Uiced the larva. This swelling was always on the lower side of 
the leaf, and caused the vein to angle slightly upwards at this point, 
noticeably tilting up the part of the leal beyond the injury. 
The beetles, in feeding, eat out the soft tissue between the 
smaller veinlets, but leave the surface layer of the opposite side, 
thus making a minute shallow pit one-half to one millimeter in 
diameter (one-fiftieth to one-twenty-fifth of an inch) closed at the 
bottom by a more or less transparent membrane, which is the dry 
epidermis of the opposite side. These pits are usually in groups 
of two or more, separated only by the veinlets and a little leaf- 
tissue. The beetles usually feed on the lower surface, but some- 
times on the upper surface also, especially on woolly-leaved varieties. 
As an effect of these injuries the leaves become ragged near the 
tip and riddled with small holes. 
Injuries by this species are not uncommon thruout south- 
ern Illinois, and in some places were abundant enough to be of 
economic importance. In one orchard Mr. Taylor counted fifty- 
eight mined leaves on a single branch three feet long, and col- 
lected several hundred leaves bearing the characteristic pupal cham- 
ber. In another orchard, visited by Mr. Titus and the writer, the 
beetles were very abundant on the leaves, which were thickly and 
conspicuously peppered with small pits. 
LIFE HISTORY AND HABITS 
The eggs are apparently inserted in the outer part of the leaf 
in one of the principal veins. The young larva begins to mine the 
leaf near by, invariably starting toward the outer margin. Upon 
nearing this it enlarges the mine in all directions, obliterating all 
or a large part of its original passageway. The mine remains quite 
flat until the larva is about full-grown, when it becomes hemispher- 
ical above and slightly swollen below; and in the chamber thus 
formed the larva pupates. The adults emerge from the chamber 
by breaking it open at the center on either the upper or the lower 
side. When touched they leap away with a quick snap, like the 
flea-beetles; when the leaf on which they are feeding is disturbed, 
they feign death and drop to the ground. 
The earliest date for this insect is April 27, for the completed 
leaf mines at Carbondale; the earliest record for the adult is in a 
note by Taylor to the effect that he has seen the beetles abroad for 
several days before May 15. The adults have emerged in largest 
numbers during the last week in May from many mines collected 
in different years, and the latest date of emergence was June 4. The 
beetles were seen by us on apple leaves thru the month of June, 
