276 GEO. H. HORN, M. D. 



The species of this genus are very troublesome to define, from their 

 variability in color and their tendency to vary in sculpture. The fol- 

 lowing table will assist in their determination, and although prepared 

 with considerable trouble is not a perfect guide but rather an aid. 



Hind angles of thorax broadly rounded or very obtuse. 



Thorax evidently narrower than the elytra, disc subdepressed yuccse. 



Thorax as wide as the elytra, disc convex. 



Thorax narrowed in front, anterior angles rounded. 



Elytra uniform in color but variable from piceous to yellow. 



]>allipennis. 



Elytra piceous with yellow basal and apical spaces lieatipteriis. 



Thorax quadrate, anterior angles distinct luutilaliis. 



Hind angles of thorax distinct but sometimes retracted. 



Sides of thorax with a short posterior sinuation, hind angles retracted. 



Eobust, densely finely punctured, subopaque luelanopterns. 



Oblong, depressed, sparsely punctate. 



Ferruginous, shining, elongate, prosternum smooth at middle. 



teiiipestivas. 

 Piceous, subopaque, oblong oval, prosternum densely coarsely punctured. 



decipiens. 

 Sides of thorax not sinuate, hind angles rectangular. 

 Thorax very distinctly narrower at apex than base. 



Sides arcuate, surface opaque lliger. 



Sides straight, surface feebly shining niarginatus. 



Thorax subquadrate, not or very feebly narrower at apex. 



Surface opaque, densely punctured corficinus. 



Surface moderately shining, sparsely or inconspicuously punctured. 

 Prosternum in front nearly smooth. 



Piceous, nearly black, color uniform brachypterus. 



Piceous, elytra with large pale discal spot on each (iiscoideus. 



Prosternum in front densely, rather coarsely punctured. 



Punctuation of surface rather coarse and sparse. Hind tibise of male 

 suddenly broader at apical half antiquus. 



C yuccai Crotch, {Colasius).—'Piceous black, feebly shining, oblong oval, 

 narrower in front. Head densely punctulate. Thorax one-half wider than 

 long, slightly narrower in front, sides moderately arcuate, hind angles rounded, 

 base slightly sinuate on each side, surface densely punctate. Scutellum moder- 

 ately densely punctured. Elytra slightly wider than the thorax, a little longer 

 than wide conjointly, apices obliquely truncate, surface densely punctured like 

 the thorax. Abdomen above rather more sparsely punctured than the elytra. 

 Body beneath densely punctured as above. Length .18— .24 inch; 4.5—6 mm. 



The males present no special sexual characters other than the addi- 

 tional deflexed dorsal segment and the emarginate fifth ventral. 



I cannot see why Mr. Crotch placed this species in Colastus, all the 

 characters being those of Carpophilus. 



Occurs abundantly in the Mojave Desert, in unopened flower heads 

 of Yucca* 



