THE POPLAR AND WILLOW BORER 



469 



The mature larva (fig. 122) is a thick, legless grub, resembling that of 

 the June beetle. It measures from 12 to 13 millimeters in length, with 



a maximum width of 4 millimeters. It is 

 white or yellowish white in color, with a 

 reddish brown head. The heavily chitinized 

 mouth parts are black. There are no out- 

 standing markings that distinguish this grub 

 from many other wood- 

 boring larvae, and the ' 

 surest way of identifica- 

 tion is by its habits. 



The pupa 



Pupation begins in the 

 last few days of June and 

 continues throughout July. 

 The pupal period varies 

 from ten to eighteen days, 

 depending largely on 

 weather conditions. Pupx 

 formed early in July re- 

 quire only ten days, while 

 those of late July require 

 as long as eighteen days, 

 to transform into adults. 

 From two to three days 

 are required for the adult 

 to become fully colored 

 and hardened. Those ma- 

 turing early in the season 

 usually remain in the pupal 

 cells for two or three weeks 

 before emerging. A general 



emergence of the adults occurs during the latter part 



of July. The beetle, when ready to leave, simply cuts 



its way out through the frass that had been packed in 



the burrow by the larva before pupation. 



The pupa (fig. 123) measures 9 millimeters in length. 



It varies from almost white to yellowish in color, the 



brown spiracles showing distinctly. Scattered over the dorsal surface are 



many small spines. Some of them stand out prominently on the pro- 



FIG. 1 20. PUPA IN SITU 



FlG. 121. THREE 

 PUPAL CHAMBERS 

 FORMED IX A 

 TWO-YEAR -OLD 

 CAROLINA POPLAR 



