ip4 BULLETIN 407 



do not make them. These were evidently the holes to which Hopkins 

 (1897) referred when he stated that the numerous holes in the bark indi- 

 cated that the adults had emerged, altho nothing but fully matured 

 pupae were found in the wood. 



When the pupal cell is hollowed out, the larva, by means of its mandibles, 

 splits off some splinters very much resembling short pieces of excelsior, 

 \ to | inch long, from the sides of the burrow. With these it closes up 

 the pupal cell a short distance below the point where it begins to run 

 parallel to the grain of the wood. After these splinters have been packed 

 firmly in place, so as to form a compact plug, they are reinforced on the 

 inside with a plug of sawdust. 



In fallen timber, the pupal cells may extend in either direction, but 

 in standing timber all those examined by the writer extended downward. 



The prepupal stage 



When the pupal cell is completed, the larva ceases activity and passes 

 into the prepupal stage, during which it is found at the further end of the 

 cell, always facing the plug of splinters and sawdust. However, if the 

 plug is damaged or destroyed, more sawdust will be gnawed to repair 

 the damage. During this stage both the length and bulk of the larva 

 slightly decreases. The duration of the prepupal stage varies with the 

 temperature and humidity. In the laboratory, where it was warm and 

 dry, this period lasted, on an average of fifteen days, while in the insectary, 

 under normal conditions, it was much longer, lasting from twenty-three 

 to sixty-three days. During the latter part of the prepupal stage, the 

 color of the larva varies from a yellowish white to a brownish color, and 

 the antennae and various other appendages become faintly discernible 

 thru the transparent cuticula. 



The pupa 

 Pupation 



In the laboratory, pupation began as early as August 23, while in the 

 field the first pupae were found on September n. Pupation continues 

 from this time until November 12, by which time all the larvae have 

 changed to pupae, the majority of them transforming during the month 

 of October. The last larval skin may remain attached to the end of the 

 pupa, or else lie free in the pupal cell. 



Activities of the pupa 



Thruout this stage the pupa remains at the further end of the pupal 

 cell, facing the plug of splinters and sawdust. It remains quiescent 

 unless disturbed, at which time the abdomen is moved back and forth. 



