DANGER OF SPREAD OF GIPSY AND BROWN-TAIL MOTHS. 17 
Seasonal History. 
The moths emerge from the pupz irom the middle of July to the middle of August, 
the date varying considerably according to the season. After mating they live buta 
short time, and the female dies after depositing her eggs. 
The eggs are laid therefore in July and August. They are deposited by the moths 
on the trunks of the trees upon which the caterpillars have lived, and in fact usually 
in the vicinity of the place where the female has transformed. The caterpillars before 
transforming frequently crawl for some distance from the trees upon which they have 
been feeding, and it therefore happens that the egg masses will be found on fences and 
in all sorts of protected situations in which the caterpillars hide during the day. The 
crevices in stone fences often contain very many of these egg masses, and knot holes 
in old trees will also contain many which would not at first be 
discovered. The egg masses are found also in hollow trees, in 
crevices under rough bark, on shrubbery, on buildings, in wood- 
piles, in barrels, in boxes, and among rubbish in dooryards. 
The moths seem to choose the inner or lower surface of an object 
upon which to lay their eggs, and therefore egg masses are placed 
out of sight perhaps as often as in sight. 
The eggs hatch about May 1, and the young caterpillars begin 
immediately to feed, usually upon the lower surfaces of the 
leaves. As they grow they cast their skins several times, and 
as they become larger they feed only at night, hiding during the 
daytime, usually in clusters on the shady side of tree trunks, 
beneath large limbs, in holes in trees, under loose bark, and in 
fact under any near-by shelter. It is the habit of most of them 
to descend before daybreak upon the trunks of the trees and to 
seek for such shelters as those just indicated, returning after 
nightfall to resume their nocturnal feeding. 
The larvee usually become full grown about the 1st of July, 
and then transform to pupz. The pupe are found in the same 
situations as those we described for the egg clusters, but are 
found also in the foliage of trees and shrubs. 
How the Insect Spreads. 
Fig. 2.—Full-grown 
As indicated above, the bodies of the females are so heavy caterpillar of the 
as to prevent flight. Therefore the insect must be principally needy hes 
ural size. (From 
distributed while in the caterpillar or larval condition. The cat- Tuseet Life.) 
erpillars are active crawlers, but asa rule do not migrate from the 
localities where they were born except when food is scarce. When young, and when 
there is hardly enough food, the larvee spin down from trees by means of silken threads 
and often alight upon vehicles of one kind or another, and are thus carried often for 
great distances from the place of birth. Trolley cars, carriages, automobiles, and bicy- 
cles are thus means of transportation almost unlimited in their possibilities. The 
caterpillars often crawl upon vehicles which happen to stand for any length of time in 
an infested locality, and thus may be carried great distances. Sometimes even pe- 
destrians aid unwittingly in this distribution, since the caterpillars may drop by their 
threads upon the garments of a person passing under an infested tree. 
The species may be transported, too, in the egg stage on nursery or ornamental 
stock, as already noted, and it has been shown that the egg clusters are laid upon many 
different kinds of objects. Cord wood stacked and piled may be carried away in the 
autumn bearing many egg masses, and, if not burned before summer, larvee may issue 
in a new locality. - The same may be said for lumber piles near infested trees. Freight 
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