18 
BULLETIN 427, TJ. S. DEPARTMENT OF AGRICULTURE. 
are, naturally, all degrees between these extremes . There seems 
to "be no true hibernation of the egg, those which develop slowly 
passing through about the same color changes and requiring about 
the same time in proportion as those which develop very quickly. 
There is more or less regularity in hatching of the eggs deposited, 
even where the period of incubation is the longest. In the case of 
those which took 34 
days, all which were 
deposited during one 
night hatched during 
36 hours. Practi- 
cally all the uniii j ured 
eggs hatch success- 
fully. From a count 
kept of those depos- 
ited under laboratory 
conditions only 5 out 
of 730 eggs failed to 
hatch ; of these 4 were 
sterile, and the other, 
after partial develop- 
ment, collapsed. 
The shells of the 
eggs, as indicated by 
the color changes be- 
fore hatching, are 
very thin and collapse 
. shortly after the lar- 
vae leave them. 
THE LARVA. 
EMERGENCE AXD FEEDING 
HABITS. 
The larva emerges 
by eating a hole 
through the eggshell. 
The newly hatched 
larva is about 1 milli- 
meter in length and 
is quite light in color with the exception of the head, which is dark 
brown; it is inconspicuous and very difficult to detect when on the 
surface of a potato. 
The larvae are quite active and begin feeding almost at once. They 
seldom move far from where they hatch before they begin to burrow. 
When the egg is laid on a leaf there is slight chance that the larva 
Fig. 15. 
-Potato tuber-moth injury to exterior of fruit of eggplant. 
(Original.) 
