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1920] Blackman — New Species of Pityophthorus from Colorado 5 



regularly rounded; tips not acuminate; strial punctures moderately 

 fine, in regular rows except near base where they are somewhat con- 

 fused, first stria impressed, the others not; interstrial punctures fine 

 and very sparse, almost lacking on the disc; disc nearly glabrous 

 but with a few small hairs, these becoming longer and more numer- 

 ous at the sides and behind; declivity steep with deep, rather narrow 

 sulcus; suture granulate and widened toward apex; lateral eleva- 

 tions abrupt and granulate; granules of the 3rd and 4th interspaces 

 forming two rows which converge and become confused near apex, 

 those of 4th interspace smaller but distinct, others more or less 

 confused, each of granules with a rather long stiff tactile hair arising 

 from near its base. Ventral abdominal segments rather finely 

 punctured and moderately hairy; last segment deeply and broadly 

 emarginate. 



Female, of the same general proportions. Front flattened, with 

 nearly circular pubescent area bordered by coarser and longer in- 

 curved hairs; prothorax as in male; apex of elytra more acutely 

 rounded but not acuminate; declivity not so steep, sulcus not so 

 deep, lateral elevations not so pronounced, with a sparse row of 

 minute granules on the 3rd interspace and a few scattered ones 

 lateral to it; long tactile hairs absent. 



Host tree: Picea engelmanni Englm. 



Locality: From Pitkin, Colo., collected by Mr. R. O. Bassett, 

 Jr., October, 1915. 



Explanation of Plate I. 



Fig. 4, 5. Slabs from the trunk of Engelmann spruce showing 

 the engravings of P. bassett i in the inner bark and the exit holes 

 through the outer bark. About two-thirds natural size. 



Fig. 6. Two segments from the limb of a balsam fir, showing 

 the engravings of P. bassett i on the surface of the sap wood. About 

 three-fifths natural size. 



