8 BULLETIN 1469, U. S. DEPARTMENT OF AGRICTTLTUBE 
Under laboratory conditions hatching occurred in from 12 to 19 
days after egg deposition, the average time being 15 days. 
THE LARVA 
[PI. 1, 1, 6; text fig. 3, B, C, D] 
There is a slight variation in the markings of the larvae, as well as 
in the length and in the width of the head of the different larval 
stages. The following descriptions and measurements are for the 
average larvae in each stage. 
FIRST-STAGE LARVA 
Newly hatched larva 2.5 mm. long. Head brownish and 0.43 mm. in width ; 
flat on front, with a few short spines. Mouth parts lighter in color. Thoracic 
legs brown. Body brownish yellow, with rows of darker brown tubercles, 
thickly studded with short brown spines and with a small number of long hairs. 
First thoracic segment provided with brownish dorsal shield. 
The first-stage larvae leave the egg mass soon after hatching and 
begin feeding on either side of the leaf, but more often on the under- 
side. They eat the epidermis only, avoiding even the smaller veins. 
After five or six days each larva incloses itself within a small web, 
where it molts. Very soon after molting the second-stage larva 
crawls from the molting web and begins feeding. 
SECOND-STAGE LARVA 
Newly molted larva 4 mm. long. Head 0.55 mm. wide, black, with lighter 
colored mouth parts. Body dark brown, with rows of dark-brown tubercles 
Thickly studded with short brown spines and a few long hairs. Thoracic legs 
dark brown to black. First thoracic segment with dark-brown dorsal shield, 
similar to the one in the first-stage larva. Dorsum of the second and third 
thoracic segments, and the third, fourth, fifth, eighth, and ninth abdominal 
segments, yellowish white. Dorsum of the sixth and seventh abdominal 
segments provided with retractile tubercle. 
The second-stage larvae feed for five to six days, in the same man- 
ner as do the first-stage larvae. Since the larvae of both stages con- 
fine their feeding to the epidermis of the leaves, they do not defoliate 
the trees as do the larger caterpillars. In heavy infestations the 
feeding by the small larvae is often severe enough to cause many of 
the leaves to turn brown and drop, making the trees unsightly. 
"When through feeding, the larvae construct hibernating webs, in 
which, soon after their completion, another molting occurs. 
HIBEBNACTJLTTM 
The web made by the second-stage larva is much stronger than the molting 
web of the first-stage larva, and within it the third-stage larva passes the 
winter. Usually there is a single larva within each web, but occasionally. 
in heavy infestations, several larvae hibernate under the same web. The 
hibernating webs (fig. 3, E) are placed in crevices and depressions, ranging 
from deep to very slight, in the bark on the tree trunks and branches. They 
are sometimes found on small twigs, and even on leaf scars, and are present 
from the top to the bottom of the trees. They are very inconspicuous, closely 
resembling the color of the bark. In shape they are irregular, with a circular 
or oval outline, usually about 4 mm. in length and 1 or 2 mm. wide. Occasion- 
