32 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



densely granulate, coarser in impression, pubescence fine, 

 inconspicuous. Elytra with the sides parallel, interspaces 

 1, 3, 5, etc., very narrowly, acutely, evenly elevated through- 

 out their length, strial punctures coarse, close set, even in- 

 terspaces appearing obsolete, the oblique seise yellowish, 

 exceedingly fine, scarcely perceptible. Head with side mar- 

 gins strongly reflexed, slightly diverging posteriorly, front 

 rather coarsely evenly granulate, with a distinct median 

 tubercle simplex Lee. 



Lower California (Cape San Lucas). 



Length 2.2 mm. Species stouter, fuscous, legs, and antennae 

 ferruginous; pronotum longer than broad, narrower poster- 

 iorly than elytra at base, side margins straight or feebly 

 arcuate, convergent posteriorly, anterior angles very broadly 

 and the posterior obtusely rounded, median impression 

 broadly impressed, elongate, attaining the anterior margin, 

 two pairs of short acutely elevated costse extending into it 

 for about one-fourth its length one pair from anterior and 

 the other pair from posterior margin, a feebly elevated 

 sinuous costa between impression and margin, surface 

 densely evenly granulate, coarser in impression, the pu- 

 bescence, especially on the costse, silvery and very conspicu- 

 ous. Elytra noticeably flattened dorsally, parallel, inter- 

 spaces 1, 3, 5, and 7 equally feebly rather obtusely elevated 

 and finely tuberculated, even interspaces appearing nearly 

 obsolete, finely granulate, each granule bearing a conspicu- 

 ous seta obliquely inclined posteriorly. Head with side mar- 

 gins strongly reflexed, front densely evenly granulate, with 

 a prominent median longitudinal strongly elevated ridge. 



planipennis, n. sp. 



Arizona (Grand Canyon Station). 



SUBDIVISION D. 



Pronotum with a distinct longitudinal elevated costa between 



the median impression and the lateral margins SECTION A5 



Pronotum without trace of such costa SECTION A6 



SECTION A5. 



Length 2 mm. Body stout, pronotum about as wide as long, 

 posteriorly narrower than elytra, sides nearly straight and 

 convergent posteriorly, median impression broad, deep, a 

 pair of very short acutely elevated lines within it at anterior 

 margin and a similar pair very poorly defined or obsolete at 

 anterior margin at either side, a single longitudinal costa be- 

 tween impression and side margin, surface densely evenly 

 covered with sharp setigerous granules, which become 

 coarser and tuberculate within the impression; elytra broad, 



