90 GEO. H. HORN, M. D. 



primarily by the male sexual characters ; secondarily it will be ob- 

 served that the thorax here is shorter and more abruptly narrowed 

 at base. 



Occurs in Canada, New York and the New England States. 



19. C triiiervia Kby. — Form nearly that of femornfa, subdepressed, pice- 

 ous, with aeneous surface lustre, the punctured spaces of the elyti'a cupreous, body 

 beneath cupreous; antennee bronzed, gradually more slender to tip, third joint 

 as long as the next two ; front green, rather flat % , cupreous, slightly convex 9 , 

 coarsely and closely punctured, with two small callosities; clypeus (91) broadly 

 triangularly emarginate at middle, the notch sometimes oval at bottom, on each 

 side arcuate ; thorax twice as wide as loug, sides rather abruptly wider in front, 

 then slightly convergent and near the hind angles abruptly narrowed, but less 

 so than in front ; disc moderately convex, a moderately deep median sulcus 

 densely punctured, on each side an ii-regular elevation, near the sides usually 

 with two tubercles placed obliquely, the surface otherwise densely and coarsely 

 punctured ; elytra parallel, narrowed at apical third, the margin serrulate, the 

 apices obtuse ; disc subdepressed, with three more or less interrupted costse. with 

 intercurrent elevations, the fourth costa close to the margin and inconspicuous ; 

 intervals between the costfe with alternating, densely punctured, and smoother 

 spaces ; body beneath sparsely punctate ; prosternum not lobed in front ; anterior 

 femur with a broad but obtuse tooth, feebly serrate on its outer edge ; last ven- 

 tral segment with the margin serrulate. Length .36 - .56 inch ; 9-14 mm. 

 (Figs. 90 and 95.) 



Male. — Prosternum very densely punctured and finely pubescent ; anterior 

 tibia (94) arcuate, riither abruptly dilated at tip, the dilatation being a lamina 

 arising from the posterior side of the tibia; middle tibia less arcuate, gradually 

 broader to tip, the posterior tibia straight; last ventral segment (92) broadly 

 semi-circularly emarginate, the last dorsal sparsely punctate with a triangular 

 emargination. 



Female. — Prosternum coarsely, sparsely punctate ; anterior tibia slightly arcu- 

 ate, gradually wider to tip, the middle less arcuate, not thicker, the posterior 

 straight ; last ventral (93) longer than in the male and with a small semi-circular 

 emargination ; last dorsal more punctate than in the male, a vague median sul- 

 cus and a small apical notch. 



As is usual in a species with wide distribution the facies is ex- 

 tremely variable. This results from the greater or less i)rominence 

 of the costse and their extent as well as from the variable j^unctua- 

 tion. From the aggregate, which has heretofore passed as trinervia 

 in (>ur cabinets, I have separated a number of species — some of which 

 follow immediately — others belong to the series with the prosternum 

 feebly lobed in front. These differ in their sexual characters in ad- 

 dition to the presence of the lobe. There remains, notwithstanding, 

 the separation of these, an aggregate of variable facies with all inter- 

 grades of form and sculpture, which must by their sexual characters 

 be considered trinervia. It will therefore be necessary in examining 

 specimens to look closely to the sexual characters. 



