THE CALIFORNIA PEACH BORER. 75 



they are found in a tree which has been completely girdled and dies 

 prematurely. 



A cocoon may be placed 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 

 that 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 OP 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. 



