384 



WEST VIRGINIA EXPERIMENT STATION 



in the bark or the wood_by the larvae, which extend from the 

 egg gallery and are small at first and gradually incaease in size 

 as the faither end or terminus is approached; thus differing 

 from larva chambers which are of equal diameter throughout, 

 and seldom exceed but little the length of the larva, pupa, or 

 newly developed adult. 



Pupae^ cases. This term refers to the cavity in the wood or 

 bark at the terminus of the 

 larva mines, which is exca- 

 vated by'the matured larva, 

 and in which it changes to 

 the pupa. 



Brood exits. This re- 

 fers to the holes in the bark, 

 often called "shot holes," 

 which extend from the 

 pupa cases to the surface 

 and are excavated by the 

 newly developed adults of 

 a brood when they are 

 ready to emerge. These 

 exit holes in the bark differ 

 from the main and side en- 

 trances to the galleries, in 

 the fact that they are clear- 

 cut and are exposed or conspicuous openings; whereas those of 

 the entrance to the galleries, are as a rule, obscured by crev- 

 ices in the bark, or by elevations or projections on the surface; 

 and also by a living or dead beetle which is often stationed at 

 the entrance. 



Hibernating burrows- These are made by the adults in 

 the outer bark and wood of the dead and dry branches and 

 twigs in which they pass the winter. 



Food burrows. These are cavities or burrows excavated by 

 the adults in the living bark, and at the base of small twigs, 

 buds, or leaves, solely for the purpose of obtaining food. 



Preliminary burrows or galleries. These are the same or 



Fisr. LVI. Pupa cases of Tomicus calli- 

 graphus in pine bark . 



