THE GRAPE LEAF-FOLDER. 7 
LIFE HISTORY AND HABITS. 
The moths of the grape leaf-folder issued in greatest numbers 
during the early part of May, from pupae overwintered in jars in the 
out-of-door rearing shelter at Washington, D. C. This maximum- 
emergence date will vary, of course, with different localities, owing to 
variation in humidity and temperature. Moths were obtained over 
a much longer period, including the latter part of April, all of May, 
and most of June. 
About 60 minutes is consumed by the insect in emerging from the 
pupal skin, the operation commencing with a circular abrasion at the 
head end. The number of females to issue was greater than the 
number of males by approximately seven to one. Numerous moths, 
both males and females, were confined in jars for several days and 
fed on honey and water, but at no time was mating or oviposition 
observed. 
The adults when disturbed fly rather quickly, but as a rule they are 
to be found at rest on the underside of the leaves (PI. I, i; PL II, c). 
The eggs are usually deposited singly on the underside of the leaf (PL 
I, a) along the midrib or other veins, or in the angles formed by the 
branching of the veins. The writer has found eggs scattered over 
the grape canes, as has been recorded, and the finding of them on the 
leaves has been corroborated by other observers. 
The young larvae, about one thirty-second of an inch in length 
(fig. 2, &), emerge from the eggs in 8 or 10 days, and as they are unable 
at this time to fold the leaves, search out a sheltered place among the 
foliage, or even crawl into the folded shelter made by an older larva, 
where they commence feeding upon the upper epidermis of the leaf. 
During its life the larva molts six times, the thoracic markings 
becoming darker with each molt. During the periods of three or four 
days between molts the larva feeds almost continuously, though it 
is especially active at night. 
When about two weeks old the larva makes a small fold in the leaf. 
It commences the operation by spinning strands of silk from side to 
side, across a portion of the leaf near the edge, each successive silken 
strand being shortened until the edge of the leaf is gradually drawn 
over and fastened with shorter bands of silk. It has been thought by 
some investigators that among the leaf-tying and leaf-rolling larvae 
the folding and fastening of the leaf is not so much the product of 
actual strength exerted by the immature larva J but is the result of 
solidification of the newly-produced silken strands in drying. Within 
this shelter the larva spins a further protection, composed of many 
recrossed strands of silk (fig. 3). If its shelter is torn open, the larva 
wriggles violently and usually falls to the ground. 
The attacks of a larva are not necessarily confined to a single leaf. 
In rearing experiments conducted in jars two leaves usually consti- 
