448 Goleopterological Notices, V. 



Among' the fifteen representatives of the first group in my cabinet 

 there is only one female, while among the sixteen specimens of the 

 second group there are only three males. This indicates without 

 doubt a difference in the life habits of the species composing the 

 two sections of the genus, which should perhaps be treated as sub- 

 genera. The peculiar conformation of the elytral strias mentioned 

 by me in the description of montanus (Bull. Cal. Acad., II, p. 419) 

 is a malformation ; it is not observable in any other of the nume- 

 rous examples in my cabinet, many of which are from Sta. Cruz Co. 



O. cavicatlda n. sp. — Moderately stout, convex, shining, dark rufo- 

 testaceous throughout ; pubescence moderate in length, rather abundant. 

 Head much wider than long, very slightly narrower than the prothorax, sub- 

 hexagonal, the eyes small, much nearer the base than the apex, the tempora 

 strongly convergent, rather longer than the eye and nearly straight ; fovese 

 deep, widely separated, connected by the usual deep parabolic groove ; 

 antennal tubercles strong, each with a deep rounded fovea immediately above 

 and behind the point of antennal insertion ; surface polished, subimpunctate, 

 beneath minutely punctate and finely, densely setose ; antennae short, stout, 

 the tenth joint fully twice as wide as long, eleventh stout, conoidal, as long 

 as the preceding four. Prothorax about as long as wide, widest at the middle ; 

 sides convergent and roanded to the apex, convergent and straight to the 

 base ; apex narrower than the base, subtubulate ; lateral teeth small but well 

 formed and distinct ; disk with the usual fovese and sulci, rather coarsely 

 feebly and sparselJ^ punctate, the punctui'es becoming granuliform near the 

 base. Elytra not as long as wide, one-half longer and fully three-fourths 

 wider than the prothorax, the three discal strise deep, rather short, none ex- 

 tending much beyond the middle. Abdomen scarcely longer but a little nar- 

 rower than the elytra, the first dorsal constituting one-half its total length 

 from above, the basal impression two-thirds of the total width, not carinate. 

 Length 1.4 mm. ; width 0.5 mm. 



California (Marin Co.). 



A single male, having the third dorsal acutely produced in a tri- 

 angular lobe, the fourth vertical, concave, not visible from above, 

 glabrous, polished, impunctate throughout except abruptly, densely 

 so along the lower margin. With the male type is associated a 

 female from Siskiyou, which agrees very well. This is by far the 

 smallest known species of the genus. 



In all of the species of this genus the elytra have, along the apical 

 margin, an even row of small slender porrect and strigose scales. 



