THE CALIFORNIA PEACH BORER. 75 
they are found in a tree which has been completely girdled and dies 
prematurely. 
A cocoon may be Alnced with its anterior end directed upward, 
sideways, or downward, and it usually has a clearly open space in 
front, so that the pupa will not be hampered in getting out and so 
thet the issuing moth will also find an easy exit. Of 26 empty pupal 
cases collected on July 20, 1908, from a completely girdled dead tree, 
15 were so placed that the emerging moths could escape directly to 
the open air, but 11 were found under the large expanse of dead 
bark and could get out only through rather distant openings. 
DESCRIPTION OF PUPA. 
The late Prof. Slingerland, in his bulletin on the eastern peach- 
tree borer, states that the male pupa can be readily distinguished 
from the female by its more slender shape and smaller size and by 
the double row of spines across the seventh abdominal segment, 
which bears the last or caudal spiracles. These same sexual differ- 
ences are also clearly characteristic of the western borer. 
The pupa is normally dark-brown in color. It is, however, very 
light brown when first formed and almost black-brown just before 
the moth issues. The beaklike anterior tip is strong and sharp and 
easily cuts through the weak anterior end of the cocoon. In leaving 
the cocoon the mature pupa hitches itself forward by means of the 
numerous backwardly directed dorsal spines and forces itself about 
half way out from the cocoon, and immediately the shell splits along 
the dorsal side and the moth issues. The posterior end of the pupa 
remains fastened to the cocoon for an indefinite period after the moth 
has gone. 
LENGTH OF PUPAL PERIOD. 
The individual pupation record given in Table IV indicates clearly 
the length of time required in the several changes during the process 
of pupation. 
