8 BULLETIN 600, IT. S. DEPARTMENT OF AGRICULTURE. 
kept outdoors in glass jars transformed to moths 7 days after 
becoming pupae. 
HIBERNATION. 
This species, judging by analogy, passes the winter months as a 
larva. The behavior of individuals kept in the insectary, however, 
should be mentioned in this connection. Larvae collected in the field 
August 23, October 16, and November 1, 1915, the last date being 
the latest when larvae were taken outdoors in 1915, were placed in the 
insectary. Here they constructed above the surface of the soil rather 
tough, brownish, silken cocoons of a more substantial nature than 
those from which moths issued during the summer months. Exami- 
nation of some of these cocoons, made as late as December 11, showed 
that they contained inactive larvae. - The exact date when pupae were 
formed was not ascertained, but moths began to issue as early as 
May 10. From observation it would appear that eggs are first de- 
posited outdoors about this time. 
On October 10, 1916, larvae were found, in cocoons similar to those 
mentioned above, in a field of sweet potatoes at Baton Rouge. These 
cocoons were found at the surface of the soil, in portions of old, dead, 
sweet-potato leaves. 
In southern Texas, according to Mr. High, the last generation 
doubtless passes the winter in the last larva instar and pupates in 
the spring or late in the winter. He has observed that the mature 
larva of this generation spins a cocoon of strong, silk during the first 
half of November and remains in a quiescent state until ready to 
pupate. The cocoons usually are covered with soil or leaves, although 
any material the larva is able to draw together may be utilized. 
Where no such material is available it will make the cocoon entirely 
of silk. 
THE LIFE CYCLE. 
The minimum time required for the various stages in the insectary 
at Baton Rouge was as follows : 
Days. 
Egg stage- 4 
Larva, stages ^ - -r--_ 13 
. Prepupa stage- ^ 2 
Pupa stage 6 
Total life cycle— 25 
In June larvae were found in a cage 7 days after newly emerged 
moths had been placed therein, so that it appears that moths may 
begin egg-laying within at least 3 days after they have issued. This 
would give a minimum total of 26 clays for the life cycle. 
Under normal outdoor conditions the time necessary for the life 
cycle probably would be somewhat longer than that required in the 
