18 
to the larvee of this order of insects. The cocoons of the early gener- 
ation are fragile and not so heavy or well made as those of the later 
generation, in which the larva passes the winter. 
THE PUPA. 
The larva when spinning its cocoon is bent upon itself, but when 
the spinning is completed it straightens and becomes shorter and 
thicker. In about five days it sheds its last larval skin and becomes a 
pupa. One can always find this skin ina pellet at the caudal end of 
the pupa. The pupa is about half an inch long and at first is a pale 
yellow color, later becoming brown. The last day before the moth 
emerges it assumes a bronze color. The antenne, mouth-parts, legs, 
and wings of the moth may be clearly seen, all soldered together in an 
immovable mass. The segments of the abdomen are moyable and are 
armed on their caudal edge with spines which point backward. 
Some time after the beginning of warm weather in the spring, or 
twenty-one or twenty-two days after commencing the spinning of the 
cocoon, in the summer, the moth emerges. The pupa pushes itself 
through the wall of the cocoon and out free from any obstruction. 
This is accomplished by rapid movement of the abdomen, aided by 
the spines which point backward. Pup were observed to have 
moved themselves fully an inch before a suitable place for emergence 
was found. They sometimes thrust themselves through muslin or 
burlap when such is used for bands and neglected. Soon after the 
pupa is free from the cocoon the pupa skin splits down the back and 
the moth slowly crawls out. Many experiments were carried out to 
determine the time elapsing between the spinning of the cocoon and 
the emergence of the moth. The shortest time was twelve days, and 
the longest during the summer was twenty-eight days, with an 
average of twenty-two. Only a very small percentage emerge the 
twelfth day. 
THE MOTH. 
Upon emerging the wings of the moth are small, the legs weak, and 
the body soft. The moth clings to the bark head up (PIL. IV, fig. 1), 
the wings gradually expand, and the legs and body harden and get. 
stronger. Later the moth holds its wings for a few minutes above its 
back, like a butterfly. The wings are then replaced and the moth is 
ready for flight. During all these proceedings the moth carefully 
avoids the sunlight. After the wings are fully expanded and dry the 
moth frequently changes its position by running rapidly up the tree. 
In from ten to thirty minutes after emerging the moth usually flies to 
the lower branches of the tree and is lost as far as further observation 
is concerned. Quick, somewhat erratic flight is characteristic, the 
flight being so rapid that the eye can not follow it. 
