NORTH AMERICAN COLEOPTERA. 21 



O. rectus Lee. — Oblong, rather depressed, piceous, dark bronzed, feebly 

 shilling, legs rnfo-testaceous. Apex of thorax nearly truncate, a very slight 

 sinuation within eacli front angle; side margin straight from angles beyond 

 the middle, then with a moderately deep arcuate sinuation, the transparent 

 border begins at the front angles with regularly arcuate margin, narrower in 

 front and broad at the sinuation ; disc regularly convex, the surface coarsely, 

 closely and deeply punctate, median line deep and nearly entire, discal fovefe 

 moderate, not sharply defined, but distinctly separated, lateral impression deep, 

 broader in front and narrowed posteriorly. Elytra oblong oval, not very convex, 

 the strife composed of large, deep, closely placed, subquadrate punctures, the 

 intervals extremely narrow. Length .06 — .08 inch. ; 1.5—2 mm. PI. ii, fig. 4. 



This species is the only one in our faunii iu which the sides of the 

 thorax are straight for a distance from the apex, and in which, with 

 the deep post-median sinuation, there is a continuous transparent 

 border from the apex to the base. The punctuation of the thorax 

 is also coarser and denser than elsewhere seen, and the punctures of 

 the elytral strise larger, deeper, and every way more pronounced. 



Occurs in California (Tejon and Los Angeles) and Wyoming 

 (Como). 



O. piinctieollis Lee. — Form rather robust, head and thorax piceouslilack 

 shining, elytra piceous slightly bronzed, legs pale. Apical margin of thorax dis- 

 tinctly sinuate near the front angles, sides arcuately expanded from apex to 

 middle, thus abruptly arcuately narrowed to base, the transparent border wide 

 and filling the posterior emargiuatiou only; disc moderately convex, the punc- 

 tures moderately coarse, but not closely placed, the intervals smooth and shining ; 

 median groove deep and long, discal fovete deep, the two on each side united by 

 a moderately deep groove, lateral impressions deep and broad. Elytra moder- 

 ately convex, the strife composed of coarse, rather closely placed, subquadrate 

 punctures, the intervals about half the width of the strise. Length .06 — .08 inch. ; 

 1.5 — 2 mm. PL ii, flg. 5. 



In some specimens the discal fovese are so completely confluent 

 that the sculpture approaches the type seen in Helophorus. The 

 general sculpture of the surface, although moderately coarse, does 

 not approach that seen in rectus, but resembles more nearly that of 

 discrehis. 



Occurs in California (San Diego) and Arizona (Tucson and south- 

 ward). 



O. discretus Lee. — Form oblong, piceous, surface brown bronze, feebly 

 shining; legs pale rufotestaceous. Apex of thorax slightly sinuate within each 

 front angle and narrowly bordered with membrane; sides arcuate in front, at 

 middle abruptly notched, the angle formed rathei- acute, the emargiuatiou deep ; 

 the tran.sparent border wide behind, extending very narrowly iu front of the 

 emargination. Disc moderately convex, the punctures coarse, moderately close, 

 but not dense, intervals shining; median groove rather broad and deep, discal 



