H. C. FALL 471 



151. Pachybrachys vulnerosus new species 



"\'ery similar to innUibilii; in all respects except as follows. Front black with- 

 out pale markings, prothorax with red side margins but without basal or other 

 spots; punctuation of prothorax decidedly sparser and evidently coarser, the 

 median smooth line wider, the red side margins nearly smooth or with but few 

 punctures; elytral punctures coarser and less numerous. The maculation of 

 the elytra is nearly as in the type of instabilis and consists of two small post- 

 humeral red spots arranged transversely, a large subcjuadrate j30st median spot, 

 close to this externally a small spot on the eighth interspace, the tip, an elong- 

 gate spot on the shield, and the epipleiu'al margin at base, red. The second, 

 third and eighth striae are entire, the latter strongh^ impressed and the mar- 

 ginal interspace convex, nearly as in instabilis. 



Length 4.25 to 4.35 mm. ; width 2.5 mm. 



Distribution. — Arizona: Santa Rita Mountains (Snow). Two very robust 

 females; type in my own collection, paratype in Snow collection. 



It is quite probable that a larger series will show considerable 

 variation in maculation; the color difference between this species 

 and instnbilis given above may therefore prove unreliable; the 

 differences in punctuation however should easily separate them. 



152. Pachybrachys instabilis new species 



Black, variably marked with red or reddish yellow, the latter 

 color occasionall}" predominant in the male; surface moderately 

 shining, the prothorax with scarcely visible trace of alutaceous 

 sculpture. Eyes moderately distant; front without ocular lines; 

 front claws of male not appreciably enlarged. Ave. length 4 

 mm. Texas; Kansas. 



Head black variegated with yellow or rufous, varying to entirely black; 

 moderately punctate. Eyes separated by twice the length of the basal joint 

 of the antennae in the male, and by about three times the length of the basal 

 joint in the female. Antennae black, more or less rufous toward the base, 

 about two-thirds the length of the body in the male and half the length of the 

 body in the female; tenth joint (o^) about two and one-half times as long as 

 wide. 



Prothora.r strongly narrowed in front, widest very near the base, sides a little 

 more prominently rounded before the base in some males in which examples 

 the point of greatest width is less basal; punctuation moderately coarse, dense, 

 the median line wholly or in part narrowly smooth, side margins at most nar- 

 rowly and incompletely so; color black with side margins and two basal spots 

 red, varying to red with a median black stripe more or less dilated in front. 



Elytra coarsely densely confusedly punctate baso-suturally, striate at sides 

 and rear, striae moderately imi)ressed, eighth with subbasal interruj^tion, mar- 

 ginal interspace impimctate or with a few punctures toward the base (9); 

 shield undeveloped; color varj-ing from red or reddisli yellow with the outer 



TRANS . AM. ENT. SOC, XLI. 



