2o MEMOIRS ON THE COLEOPTERA 



tures coarse, deep and confluent laterally, small and distinctly separated 

 suturally, the larger foveae obscure; anterior tarsi only moderately dilated, 

 the third joint much narrower than the second. Length 14.8 mm.; 

 width 5.7 mm. California (Mariposa Co.). 



The type was taken by Mr. Nunenmacher on the twelfth of 

 June, 1914, but the exact locality is not stated. This also is a very 

 distinct taxonomic form. 



Omus collaris ssp. erraticus nov. female no stouter than the male 

 of antennalis, much narrower than the female of trapezicollis and slightly 

 narrower than the female of collaris, somewhat shining, the pronotum 

 dull; head distinctly narrower than the prothorax, moderately rugulose 

 throughout, the anterior punctures evident but somewhat obscured by 

 the sculpture; labral lobe prominent, truncate at tip; antennae slender, 

 moderately long; prothorax transverse, strongly obtrapezoidal, with 

 evenly and markedly arcuate sides from apex to base, the side margins 

 not quite attaining the latter; surface with fine and anastomosing lines, 

 the apical and lateral rugulosity very feeble, the basal a little more evi- 

 dent; base bisinuate; elytra oblong-oval, three-fifths longer than wide, a 

 third wider than the prothorax, the punctures coarse throughout, deep 

 and contiguous laterally, less deep, not quite so coarse and moderately 

 separated suturally, the granules small but sharp ; legs rather short. Male 

 unknown. Length 14.6 mm.; width 6.0 mm. California (Tuolumne Co.) 

 -Two examples. 



Apparently this form, which is evidently different from any of 

 the preceding allies of collaris in its more obtrapezoidal prothorax, 

 with arcuate sides, and deeper elytral sculpture, can always be 

 recognized as differing from horni or any of the numerous related 

 forms of that species by its more elongate outline. 



The horni section comprises the shortest and stoutest forms of the 

 entire subgenus, with very coarse and conspicuous elytral punctures, 

 and, as a subgroup, they impress one at first glance as constituting 

 a distinct species from either the temperatus or collaris sections. 

 The various subordinate forms before me are so numerous that the 

 differences are best expressed in a table as follows: 



Oblique sides of the prothorax broadly, subevenly arcuate 2 



Oblique sides straight to feebly sinuate submedially 5 



2 Elytral foveae distinct to conspicuous; pronotum very smooth 3 



Elytral foveae indistinct, the general punctuation closer; pronotum with 



fine anastomosing lines 4 



3 Male strongly ventricose, shining; head and pronotum alutaceous, 

 the former very obsoletely rugulose, impunctate anteriorly, the 

 labrum only slightly prominent medially; antennae moderately long, 

 not very slender; prothorax a fifth wider than long, much narrowed 



