AHT. 23 REVISION OF THE BEETLE GENUS OEDIONYCHIS — BLAKE 9 



14. Elytra with parallel sides and with distinct humeral prominences, but 

 somewhat flattened disk, eyes small, interocular space at least half width 

 of head, elytra piceous with yellow-brown margin, broader at apex. 



(31) circumdata. 

 Elytra with distinct humeral prominences and with rounded callosity at 

 base of each elytron near scutellar angle, eyes large, interocular space 

 approaching one-third width of head IS- 

 IS. Small, 3—4 mm 16. 



Large, 4 — 5 mm 17. 



IC). Shining, very finely punctate, entirely piceous with pale margins and 



apex (32) obsidiana. 



Shining, very finely punctate, pronotum yellow often with dark blotches, 

 elytra yellow with piceous fasciae or remnants of fasciae at base, middle, 



and near apex (32) obsidiana var. flava. 



17. Feebly shining, rather coarsely punctate, yellow brown with reddish brown 

 or piceous spot on head, pronotum usually immaculate or mth faint, 

 indeterminate shadings, elytra usually with reddish brown or piceous 

 fasciae or remnants of fasciae at base, middle, and apex, apical one never 

 at less than apical three-fourths. Eastern United States-— (33) scalaris. 

 Feebly shining, finely punctate, yellow brown, head and pronotum im- 

 maculate, elytra with ten to twelve small piceous spots, two or four basal 

 spots, four nearly transverse at basal fourth, four not in transverse line, 

 lowest at apical two-thirds. Arizona (34) durangoensis. 



DESCRIPTIONS OF SPECIES 

 1. OEDIONYCHIS VIOLASCENS LeConte 



Fig. 1. 



OedionycMs violascens LeConte. Proc. Acad. Philadelphia, vol. 11. 18.59, p. 81. — 

 Crotch, Proc. Acad. Philadelphia, vol. 25, 1873, p. 61. — Horn, Trans. Amer. 

 Ent. Soc, vol. 16, 1889, p. 183. 



Broadly oblong-oval, moderately convex, shining blue or violet. 

 Antennae not half length of body, siibmoniliform, black or bluish 

 black with terminal joints piceous, third' and fourth joints about 

 equal. Head shining dark blue with antennal sockets pale brown, 

 coarsely punctate about and between eyes, occiput sometimes nearly 

 smooth ; front not flat as in lugens and no median groove, interocular 

 space over half width of head, Pronotum over twice as wide as 

 long, moderately convex, narrowed anteriorly and with narrow, 

 slightly reflexed, explanate margin, very shining, faintly yet dis- 

 tinctly and sparsely punctate, punctures much denser posteriorly. 

 Scutellum rounded, shineig. Elytra oblong-oval, moderately con- 

 vex, broadly rounded at apex, with narrow margin; humeri moder- 

 ately prominent, only faint trace of depression within; punctation 

 variable, frequently deep and coarse, smoother toward apex; colot 

 entirely blue or violet. Body beneath sparsely pubescent, shining, 

 blue or violet, the tarsi piceous. 



27617—27 2 



