51 
shell. It follows the shell thus down the side, across the bottom and 
up the other side, until the anal prolegs at the posterior end of the 
body are just beneath the head. The embryo, in making its escape, 
bites viciously with its mandibles at the hard, tough membranes of 
the egg^ and gradually the spot weakens and the head of the larva sud- 
denly bursts through. It can now easily enlarge the hole until it is of 
sufficient size to crawl through. Once this is done, the larva is free 
from the egg in about two minutes. The whole process, from the 
first attempt to pierce the egg membrane until the larva is excluded, 
requires but a few minutes. In two cases where the exact time was 
noted it was thirteen and sixteen minutes, respectivel3^ 
The exit hole is usually large, with very ragged edges, situated on 
one side of the egg between the base and apex. The empty shell is of 
a translucent white, with a distinct purplish iridescence seen in cer- 
tain lights, more especially when viewed against a dark background. 
It retains its original shape. 
SHRINKING OF INFERTILE EGGS. 
The changes in external appearance undergone b}^ infertile eggs are 
sufficient!}^ different from those of normal fertilized ones to merit sep- 
arate mention. One fact is important. From thousands of infertile 
eggs laid b}^ moths in the laboratory not a single one ever hatchf d or 
showed the slightest external signs of embryonic development. Almost 
as soon as they are laid infertile eggs acquire a distinctly yellowish 
color, and wdthin a few hours begin to shrivel up. After twenty-four 
or thirty -six hours they are always greatly shrunken and are acquir- 
ing a dusk}^ color. From the very first they are higher and more 
conical than the normal eggs, this shape being accentuated by the 
shrinking, which occurs principally in an equatorial direction. 
EATING OF SHELLS AND EGGS BY NEWLY HATCHED LARV^. 
In the great majority of cases the newly hatched ]i)ollworms do not 
go immediately in search of food, but turn their attention to the 
deserted eggshell. Not content with the portion already gnawed out 
in their attempts to escape, they start anew to eat the shell. This 
may last only for a few^ minutes, or, again, may continue for nearly 
an hour. Frequently the entire shell is consumed, although often 
only one-half or three-fourths of it is eaten. What may be the benefit 
derived from eating the tough chitinous shell is rather uncertain. 
The idea that the larva derives any nourishment therefrom, or that it 
destroys the shell to remove traces of its own presence on the plant, 
can hardly be accepted. Nevertheless,' the eating is a very constant 
habit. 
After this is done the larva begins wandering about in its search for 
food. Quite often in captivit}^, when large numbers of eggs are close 
