96 



G The pronotum narrowly or moderately rounded in 

 front and with the two median marginal serra- 

 tions distinctly larger than the others. 



H The declivity closely granulate on suture and 

 convexity; the long hairs of the female front 

 dense and curved; the pronotal asperities 

 coarse and subconcentric. 



tuberculatus Eichh. Page 99. 



HH The declivity smooth with only faint traces of 

 granules; the long hairs of the female front 

 straight and rather sparse; the pronotal asperi- 

 ties fine and irregular. 



carmeli n. sp. Page 100. 



GG The pronotum moderately rounded in front with 

 the marginal serrations subequal in size; the 

 asperities moderate and subconcentric; the strial 

 punctures regularly placed; the declivital gra- 

 nules few, but distinct on suture and convexity. 

 pseudotsugae n. sp. Page 99. 



FF The declivital sulcus rather narrow and deep, particu- 

 larly in the male; the pronotum moderately rounded 

 and regularly serrate on the front margin, the 

 median 6 to 10 granules subequal; the elytra strongly 

 punctured, somewhat irregularly near the suture, 

 the interstrial punctures rather numerous. 



G The punctures of the elytral striae usually nearly 

 regular; the declivital sulcus with the lateral 

 walls oblique; smaller species, 2 mm. or less in 

 length. atratulus Lee. Page 101. 



GG The punctures of the elytral striae often evidently 

 irregular near the suture, the declivital sulcus 

 very narrow, the lateral walls perpendicular in 

 the male; length 2 mm. to 2-5 mm. 



nitidulus Lee. Page 100. 



EE Stout species with punctures usually coarse and dense, those 

 of the elytral interspaces decidedly numerous; the female 

 front densely, finely pubescent or with hairs of moderate 

 length, the male front with an acute, well-developed 

 median, longitudinal carina. 



PLATE 22. 

 BARK-BEETLE TUNNELS (ORIGINAL). 



Fig. 1, Pseudohylesinus granulatus Lee., in lowland balsam; one-third natural size. 

 Fig. 2, Ips latidens Lee., in western white pine; one-half natural size. 

 Fig. 3, Pityogenes carinulatus Lee., in western yellow pine twigs; two-thirds natural size. 

 Fig. 4, Pityogenes knechteli Sw., in lodgepole pine; one-half natural size. 

 Fig. 5, Dendroctonus simplex Lee., in eastern larch; about one-third natural size. 

 Fig. 6, Polygraphus rufipennis Ky., in white spruce bark; portions of larger Ips tunnels also 

 shown; two-thirds natural size. 



