104 BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
migrate to situations removed from the plant and bore into wood 
or similar material for shelter usually pupate within these shelter 
tunnels, provided that the moisture conditions of the shelter me- 
dium are suitable for pupation. The same statement applies to 
full-grown larA r ae which migrate from the plant and secrete them- 
selves in the cracks and crevices of lumber or underneath rubbish 
of various kinds. 
COCOON FORMATION AND LARVAL CHANGES 
When preparing for normal pupation the larva first closes the 
entrance to its tunnel with a thin silken partition and then retreats 
into the tunnel, where it forms a thin silken cocoon. Larvae which 
pupate in situations lacking the protection of a tunnel partly or 
entirely inclose themselves with similar cocoons. Some of the larvae 
spin such a meager quantity of silk that it is an exaggeration to 
describe the fabrication thus formed as a real cocoon. 
"When the cocoon is completed, the larva attaches itself thereto by 
means of the crochets on the anal legs, and then passes into a short 
semi quiescent stage preparatory to pupation. During this stage the 
head becomes inflexed and the use of the thoracic and abdominal legs 
is lost, while the abdominal segments become greatly swollen and 
show, distinctly the outlines of the pupal abdomen. 
PROCESS OF PUPATION 
As a result of pressure exerted from within, the larval skin splits 
along the dorsal line of the head and thoracic segments, and also 
down each side of the front, thus liberating the emerging pupa. As 
soon as it is freed from the larval skin the newly formed pupa re- 
volves on its longitudinal axis two or three times, in this manner 
firmly attaching its cremaster to the cocoon at the point formerly 
occupied by the anal feet of the larva. Out of a total of 141 pupae 
under observation in vertical tunnels, 118 individuals formed with 
the head pointing upward, and the remaining 23 individuals with 
the head downward. The newly formed pupa is nearly white in 
color with a longitudinal pink line down the dorsum. Permanent 
coloration proceeds very rapidly after emergence and in five or six 
hours the pupa is fully colored. Mature pupae vary from light 
brown to dark brown in color. 
ADULT HABITS 
EMERGENCE 
The emerging moth pushes off the head of the pupal skin until 
its head, thorax, and bases of the wing pads are visible. Here it 
rests for a short period before struggling completely out of the 
pupal skin. Ten individuals under observation required an average 
of two minutes for complete emergence. After emergence the moth 
escapes from its cocoon and crawls to the surface of the plant, pro- 
vided pupation occurred within a tunnel. After reaching the sur- 
face the moth clings to some convenient object until the wings become 
fully expanded and dried. Within a period of from two to three 
hours after emergence it is prepared for flight. 
