THE GENUS DENDROCTONUS. 



107 



groove and usual elevation; apex broadly emarginate, labrum with 

 apex broadly rounded, and the sternellar lobes of the thoracic seg- 

 ments with distinct foot calli. Larval type labeled "Hopk. U. S. 

 No. 196." 



There is some variation in the frontal elevation, but generally it is 

 situated slightly anterior to the middle or in the middle, while the 

 posterior angle of the front is distinctly subacute. These serve as 



FIG. 66. Dendroctonus monticolse: Egg galleries and larval mines in bark. (Original.) 



the most distinctive characters to separate the larva of this species 

 from that of D. ponder osse. 



Galleries (figs. 66, 67). The egg galleries are longitudinal, distinctly 

 to slightly winding or straight, usually grooved on the surface of 

 the wood and deeply grooved in the bark, the larval mines and pupal 

 cells exposed in the inner bark; the eggs are placed in approximate 

 groups, and the larval mines are short and broad. The egg galleries 

 differ from those of D. ponderosse in smaller size, more winding form, 

 and are often of a much greater length. 



