266 GEO. H. HORN, M. D. 



52. li. Iiirticiila Knoch. — Oblong, slightly broader behind, fuscoferruginous 

 to dark brown, moderately shining, head and thorax with erect hair, elytra with 

 lines of erect liair along the usual costte. Clypeus moderately deeply emarginate, 

 the margin narrowly reflexed, surface very densely punctured, front more coarsely 

 punctured and with erect hairs. Thorax narrower at apex, the sides more ob- 

 lique in front, the margin usually entire, sometimes more or less creuate, with 

 short cilite, surface variolately punctured, sometimes very densely, so that the 

 surface is opaque, at others with di.stinct intervals, the thorax more shining, the 

 erect hairs not long, but more abundant in the former race, a distint channel 

 along the basal margin from the hind angles to near the middle. Elytra with 

 much finer punctures, feebly impressed, rather closely placed, .so that the elytra 

 at times are rather scabrous than punctate, in every case they form a denser 

 group at the middle third of the elytra external to the sutural costie ; erect hairs 

 arranged in vittse along the lines of the costae forming thus five series, the mar- 

 gin fimbriate with longer hairs. Pygidium more convex and transverse in the 

 male, coarsely sparsely jiunctured and shining, not hairy. Metasternum densely 

 punctured, the hair moderately long. Al)domen moderately closely punctured 

 along the sides, smoother at middle, each puncture with a very short hair. Claws 

 curved, with a strong median tooth, alike in the sexes. Last joint of maxillary 

 palpi subcylindrical, not impressed. Length .65 — .75 inch ; 16.5 — 19 mm. 



Male. — Antenual club a little longer than the funiculu.s. Abdo- 

 men flattened at middle, the penultimate segment at middle more 

 depressed at its posterior half, on each side plicate. Last ventral 

 slightly concave at middle. Inner spur of posterior tibia moderately 

 long and acute. 



Fp:male. — Antennal club shorter than the funiculus. Last ven- 

 tral segment often vaguely impressed near the apex. Posterior tarsi 

 distinctly shorter than in the male. 



Variations. — The extreme forms of this species differ so greatly 

 that they might, without intermediate forms, be considered distinct 

 species. They may be divided as follows : 



Southern forms (North Carolina to Texas). These are larger, the 

 erect hairs of the surface longer and more abundant. \ Thorax very 

 densely cribrately punctured and subopaque. Punctuation of meta- 

 sternum very dense. 



Central forms (Illinois, etc.). These are smaller in size, slightly 

 more oval, the erect hairs less numerous, shorter and easily abraded. 

 Thorax rather shining, the punctures variolate and se{)arated bv 

 suKjoth, but narrow interspaces. Metasternum less densely j)unc- 

 tured. 



Eastern forms (Virginia northward and New England States). 

 These are exactly intermediate between two forms above described. 

 The thoracic punctures are large, variolate and closely phiced, but 



