AMERICAN COMPONENTS OF THE TICNTYRIIN/E 3II 



the apex, which is narrower than usual and feebly sinuate; pro- 

 thorax four-fifths wider than long, tlie sides parallel and feebly 

 arcuate to beyond the middle, then rounded, becoming rectilin- 

 early converging to the apex, which is mucli narrower than the 

 base and deeply sinuate; punctures fine and moderately close-set, 

 becoming rather rapidly coarse, close and subconfiuent toward the 

 sides; scutellum well developed, transverse, broadly angulate; 

 elytra inflated posteriorly, barely two-fifths longer than wide, very 

 obtuse at apex, much wider than the prothorax, with arcuate 

 sides, the punctures non-setigerous, fine, feeble, rather sparse and 

 confused toward the suture, larger, but still not very coarse and 

 disposed in the usual series toward the sides; abdomen finely, 

 sparsely punctulate medially. Length 6.2 mm.; width 2.9 mm. 

 Arizona bicolor Horn 



In nearl}^ all the species above described the elytral punctures 

 bear each a short, stiff, erect seta, becoming more conspicuous 

 toward the sides and more evident in some forms than in others. 

 There is visible also in most of the species, on the elvtral flanks 

 near the side margin and about two-fifths the length from the 

 base, a short longitudinal impression and the surface at the 

 humeral angles is more or less prominent, sometimes forming a 

 distinct callus, which is generally paler in color than the re- 

 mainder of the elytra. The male can frequently be recognized 

 by the acute and slightly upturned sheath, finely cleft and in- 

 closing the very slender intromiitent spicule, and the female by 

 the truncate end of the spatuliform and basally narrowed ovi- 

 duct, protected by longitudinal lateral pieces, but there is very 

 little sexual difference in the form of the body and no obvious 

 secondary sexual characters. It should be noted that the elon- 

 gate forms, having well developed wings, are virtually confined 

 to Arizona, being very rare elsewhere, while those with short 

 metasternum and abbreviated wings are by far the most abun- 

 dant type in southern California. 



It will be observed that the characters give^^n for some of the 

 above species are more or less at variance with those stated in 

 my revision, before cited. For example, on page 331, the form 

 of dubiwn is said to be slender, while in realitv the true diihiiim 

 has an unusually broad form of body. These inconsistencies) 

 in great part, arise from the fact that in my previous treatment 

 of the group I endeavored to fall in line with the then prevailing 

 tendency to lump various forms together, without due investiga- 



