24 BULLETIN 427, U. S. DEPARTMENT OF AGRICULTURE. 
pupa must continue all the time, though, of course, at a greatly 
reduced rate. For this reason this longer pupal stage must be 
classed as retarded development and could hardly be termed true 
hibernation. 
THE ADULT. 
EMERGENCE. 
The skin of the pupa splits along the dorsum of the thorax, and the 
moth by contracting itself draws its head from the pupal case. From 
this time on it is never quiet, contracting and expanding its abdomen 
and withdrawing its legs from their cases on the venter of the pupa. 
When the legs are free and the body has started to move in the case, 
the whole insect is free within a few moments. The freshly emerged 
adult generally moves very little until it has expanded its wings to 
their normal size. Sometimes the latter process is quite slow, but 
generally within a short time the wings reach beyond the tip of the 
abdomen. Even after development is apparently complete the 
moth prefers not to attempt flight for some time, but if disturbed 
either feigns death or seeks a place of concealment with a character- 
istic jerky running movement. 
For some time after emergence the adult spends most of the time 
in hiding, but if sweetened water is placed near it the insect will feed 
readily. 
HABITS OF THE MOTH. 
Under field conditions the habits of the insect are well adapted to 
protect it until the eggs are deposited. During the day the adult 
hides beneath rubbish, or if the fields are clean, under clods of earth. 
Its coloring is very protective, and it is difficult to locate the adults 
even after they have been observed to alight. They seldom fly in 
the field during the brighter hours of midday, unless disturbed, and 
then the flight is short and jerky, and on alighting they seek con- 
cealment. When they fly to the potato vines they hide beneath the 
leaves, so that they are seen with difficulty. Under field conditions 
they have not been noted to take food. The activity increases with 
the temperature, being greatest during warm nights. 
PROPORTION OF THE SEXES. 
The proportion of the sexes during the year remains very nearly 
constant and almost equal. Pupae selected at random at various 
times of the year gave the results shown in Table 3. 
Table 3. — Proportion of sexes of the potato tuber moth. 
, r + , Number 
Month - of pupae. 
Januarv 127 
April ! 200 
July I 200 
O ctober I 100 
Male. ' Female. 
Not 
emerging. 
69 
51 
7 
111 
86 
3 
95 
104 
1 
52 
43 
5 
