WOOLY BEARS. 83 
dred eggs. As the female deposits also eggs in smaller and 
less regular patches, we may say that five hundred eggs 
can be considered the real number produced by a single fe- 
male. The eggs, measuring 0.4 mm., are of a bright golden- 
yellow color, quite globular, and ornamented by numerous 
regular pits, which give them under a magnifying lens the 
appearance of a beautiful golden thimble. Before the eggs 
hatch they change to a dull leaden hue. In the course of 
about ten days in cool weather, but much sooner when 
warm, these eggs hatch. Without check the offspring of one 
female moth might in a single season number 125,000 cater- 
pillars in early autumn, enough to ruin the shade trees of 
many a fine street. This is reported from the fifth report 
U.S. Entomological Commission, but holds good only in 
regions where the insect is double brooded. Here, appar- 
ently, only one annual generation 1s found. 
The caterpillars just born are pale yellow, with two 
rows of black marks along, the body, a black head and with 
quite sparse hairs. When full grown they generally appear 
pale-yellowish or greenish, with a broad, dusky stripe 
along the sides; they are covered with whitish hairs, which 
spring from black and orange-yellow warts. The cater- 
pillar is, however, very variable, both as to depth of color- 
ing and as to markings, as is shown in Fig. 81. 
Close observations have failed to show that different 
food produces changes in the coloration; in fact nearly all 
the various color varieties may be found upon the same 
tree. The fail generation is, however, on the whoie, darker, 
with browner hairs than the spring generation. 
As soon as the young caterpillars hatch they immediate- 
ly go to work to spin a small silken web for themselves, 
which by their united efforts soon grows large enough to be 
noticed upon the trees. Under this protecting shelter they 
feed in company, at first devouring only the green upper 
portions of the leaf, and leaving the veins and lower skin 
unmolested. As they increase in size they enlarge their web 
