54 MEMOIRS ON THE COLEOPTERA 



those at the sides very feebly dilated. Length 2.15 mm.; width 1.15 

 mm. New Mexico (Fort Wingate), Woodgate. A single female. 



calamis n. sp. 



Form very broadly oval, convex, polished throughout and deep black 

 above, the under surface black; femora piceous, the remainder of the 

 legs and the antennae pale; head rather large, more than half as wide 

 as the prothorax, minutely and very remotely punctulate; antennae 

 with the joints of the club increasing slowly in width, the first joint 

 much longer than the second; prothorax strongly transverse, nu- 

 bilously pallid at the hind angles, the sides strongly converging but 

 only moderately arcuate; scutellum transversely ogival; elytra but 

 very little longer than wide, rather rapidly parabolic in outline, the 

 combined apex rather narrowly rounded; surface with impressed 

 lines accompanying the series of minute punctures, which become 

 slightly dilated and sublunate at the sides, the sculpture of very 

 minute scratches not at all dense, the surface shining throughout; 

 prosternum rather wider than usual between the coxae. Length 

 1.9-2.0 mm.; width 1.23 mm. New Mexico (locality unrecorded) 

 and Arizona (Walnut). Two female examples cessus n. sp. 



The last four species of the table represent a common and char- 

 acteristic type in the far southwestern Sonoran regions, and wick- 

 hami, as composed at present, would seem to include a number of 

 closely allied forms, of which extended series would be necessary in 

 order to arrive at an intelligent conclusion ; of the four female ex- 

 amples remaining of the southern California series, for instance, one, 

 the type specimen, is subparallel, with rapidly rounding and broadly 

 obtuse apex, and two have cuneiform elytra, much more narrowly 

 rounded at tip, both forms having elongate elytra, while the fourth 

 specimen is smaller, much shorter, with the elytra barely longer than 

 wide and rather acutely parabolic. Then, among the New Mexican 

 and Arizona examples, there are some that are much stouter and 

 more convex. The male is very rare and, in the single one at hand, 

 the last abdominal segment is gradually deflexed posteriorly, with 

 the edge produced narrowly at the middle in a rounded lobe-like 

 tooth. 



As bearing upon the incongruities noted under wickhami, I have 

 almost arrived at the conclusion that any systematic arrangement 

 of the species of Olibrus based upon constant structural differences, 

 other than those used in the table, is impracticable without study 

 of the larval forms. At first a division in accordance with the con- 

 tour of the inner margin of the metasternal bead seemed promising 

 whether broadly rounded or narrowly parabolic, but, on examining 



