Dec, I9I2.] Fall: North American Collops. 259 



are wrongly placed with exhniiis, and herein, doubtless, lies the source 

 of the erroneous recording of eximius from these Rocky Mt. States. 

 In the type the elytral punctuation is not very close, but is evi- 

 dently denser in the second example, while in the New Mexico speci- 

 men it is very dense and rugose. The legs in the type are entirely 

 black except the front and middle trochanters ; in the second example 

 the front thighs are largely pale, as are all the trochanters. 



C. nigritus Schaef. Can. Ent., June, 19 12, p. 185. 



A (^ in my collection from the Santa Rita Mts., Arizona (Snow), agrees 

 perfectly with Schaeffer's unique type from Arizona, which I have seen. The 

 prothorax is more densely punctured than in any specimen of punctatus that 

 I have seen and the second antenna! joint is more transverse. The two species 

 are very close but may be regarded as distinct if the antennal character holds 

 good. 



C. dux, new species. 



Male. — Head, antenna; except the basal and part of the second joint, meta- 

 sternum, tibiae and tarsi, black ; labrum and epistoma, base of antennae and 

 femora, reddish yellow ; elytra blue. Head finely and quite closely punctate, 

 minutely and less closely so anteriorly. Basal joint very thick and of irregular 

 form, wider than long from any view point, a subdentiform prominence in front 

 when seen from above ; second joint very irregular, the convex face black except 

 at base, and strongly emarginate and narrow in apical half when viewed from 

 beneath, claw-like appendage long; third joint transverse, its apex squarely 

 truncate, following joints moderately serrate, decreasing in width, the outer ones 

 elongate. Prothorax transversely oval, Ys wider than long, surface polished 

 and very finely remotely punctulate. Elytra somewhat depressed, about I/2 

 longer than wide, sides straight and a little divergent posteriorly, surface very 

 densely finely punctate and dull, vestiture of fine recurved whitish hairs and 

 erect black hairs, the latter shorter than usual. Length 7^4 mm. (head 

 depressed) ; width 4 mm. 



Del Rio, Texas. A single (S sent by Mr. Wickham, who retains 

 the type. 



This very large and fine species is remarkably distinct, the form 

 of the basal two joints of the antennae being quite unlike those in 

 any other of our species. 



C. marginicollis Lee. Proc. Acad. Nat. Sci. Phila., 1852, p. 164. 



Male. — Labrum, clypeus, antennae, venter, front and middle femora and 

 hind femora in part, rufous ; head behind the clypeus black with greenish 

 luster. Prothorax rufous with large black spot, often leaving only a narrow 

 pale margin ; elytra blue or violaceous ; meso- and metasternum black ; tibiae 

 and tarsi black. Basal joint of antennae triangular, about H longer than wide, 



