Diplocheila (Isorembus) assimilis (Le Conte 1844)

Diplocheila (Isorembus) assimilis Le Conte
The more or less trapezoidal form of the pronotum separates this species from all other Diplocheila excepting major and nupera (fig. 41 ). Its smaller size and punctate elytral striae distinguish assimilis from major melissisa, and assimilis is larger and has the elytral striae more clearly indicated than has nupera.
Diplocheila assimilis is ditypic, with the typical subspecies widely distributed in southeastern Canada and United States east of the Rocky Mountains, ranging southward to southeastern Texas, and being replaced in the southern one-third of Texas by D. a. planulata, which extends southward at least to Brownsville.

Diplocheila (Isorembus) modesta Casey
Diplocheila modesta Casey, 1920:203, [type specimen a female, USNM no. 47379, and one paratype male, USNM no. 47379, in Casey Coll.]
Diplocheila modesta exhibits a combination of certain diagnostic features of both assimilis and striato punctata, and for this reason it cannot be readily distinguished from either. The characters on which this species may be separated from assimilis are : smaller body, stria 7 usually deeper, pronotum with sides posteriorly incurved and sinuate and appearing narrower. From D. striato punctata, modesta may be separated more readily, as it lacks a protuberance on the dorsal surface of the left mandible, has fewer spines in the posterior median row of the hind tibiae (0-2), the integument is glossy, the elytral intervals are either flat or very slightly convex, and the body is smaller. Description. — Type, female. Montreal, Canada, 23.VII.98. A moderately convex beetle with glossy integument, resembling striato punctata in pronotal shape, and assimilis in other features. Length 12.3 mm., width 5.8 mm. Frontal impressions broad and shallow. Clypeus, labrum, and mandibles about as described for striatopunctata. Pronotum with sides arcuate, more abruptly constricted anteriorly than in assimilis, becoming slightly convergent and slightly sinuate basally; convexity and impressions average for striatopunctata group. Elytra with striae 1-5 sharply impressed, weakly punctate toward base, impunctate apically; stria 6 slightly shallower than 1-5, 7 slightly shallower than 6, but distinctly impressed and easily visible ; interval 3 of both elytra with a single puncture in apical 1/3 ±. Retractile stylus not examined.
Variation. — Data on variation in length, width, and number of spines in the posterior median row of the hind tibiae are presented in tables 17-19. Frontal impressions of the head vary from small, distinctly rounded pits to slightly larger, shallower, and less clearly defined impressions. The sides of the pronotum posteriorly vary from moderately incurved and slightly sinuate to more strongly incurved and more noticeably sinuate. The sides anteriorly appear to be more abruptly incurved in all specimens than in assimilis. Elytral stria 7 varies from faint to as strongly impressed as striae 1-6. Stria 6 is always present and distinctly impressed. The striae are generally sharply impressed but in a few specimens they are very shallow. Punctation of the striae varies from complete on 1-6 to impunctate, generally intermediate between these extremes. The intervals are generally flat, but are weakly convex in a few specimens. Retractile styli and male genitalia as in striatopunctata (3 males and 3 females dissected).