io MEMOIRS ON THE COLEOPTERA 



three-fourths longer than wide, oblong, the sides more rounding at base 

 though broadly; margin very fine; punctures rather coarse, impressed, 

 well separated, the scattered foveae large but not very deep; anterior 

 tarsi with the basal joint longer and narrower than the second, which is 

 a fourth wider than long. Length (c?) 12.7 mm.; width 4.5 mm. 

 Oregon (locality unrecorded). 



Differs from audouini, or any of its closely related forms, in the 

 narrower and more elongate, somewhat metallic elytra, which are 

 less deeply sculptured. 



Omus audouini ssp. distans nov. Female smaller and more slender 

 than in audouini; head subequal in width to the prothorax, shining, 

 rugose, nearly smooth and with sparse punctures at the middle of the 

 front, the impressions deep; labral lobe broadly advanced, truncate at 

 apex; antennae rather short and slender; prothorax nearly as long as wide, 

 finely rugulose, generally as in audouini; elytra oblong, two-thirds 

 longer than wide, widest near the middle, thence feebly narrowing to the 

 rounded, evident humeri, gradually ogival apically; punctures small, 

 impressed, everywhere very remote, the fovese numerous, very deep and 

 conspicuous; surface shining, though alutaceous; tarsi long and slender. 

 Length (9) 14.6 mm.; width 5.25 mm. Washington State (Seattle). 



Differs from audouini in its smaller size and narrower form and 

 from that, or any of its subspecies, in the very sparse elytral sculp- 

 ture and very deep conspicuous foveae. 



Ambiguus Schpp., is a species of the audouini group, stouter in all 

 its forms than audouini and with notably thicker antennae; solidulus 

 Csy., may be considered a subspecies, distinguished by the shallower 

 elytral sculpture, broader and more conspicuous lateral lobe, more 

 pubescent upper surface of the anterior male tarsi and slightly 

 less ventricose outline. The following is another subspecies: 



Omus ambiguus ssp. humeralis nov. Body rather short, stout and 

 strongly ventricose, moderately convex and shining; front nearly smooth 

 medially, with a few minute and remote punctures; labral lobe large, 

 rounded and prominent; antennae moderate in length, rather stout; 

 prothorax nearly as in ambiguus; elytra much shorter and of very dif- 

 ferent outline and sculpture, being broader at base, with much more 

 evident humeri, the punctures irregular, being moderate in size and 

 notably sparse generally on the disk, becoming rapidly coarse, deep and 

 very dense postero-externally. Male not known. Length 14.8 mm.; 

 width 5.75 mm. California (Humboldt Co.). 



I am by no means certain that this form should have a subordinate 

 status, as its facies is so different from that of either ambiguus or 

 solidulus, owing to the short shouldered elytra, having very pe- 

 culiar sculpture as stated above. 



