266 Journal New York Entomological Society. ["^'^i- ^^• 



the first and second antennal joints in the c?, warrant its separation, 

 at least until intermediate forms turn up. 



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



This species seems to be distinctly smaller than the most nearly allied 

 forms, the length of all specimens seen varying but little from 3^ mm. Its 

 most characteristic feature is the form of the basal antennal joint in the (^; 

 this is very broadly ovate triangular, about as wide as long, thick, not much 

 flattened in any aspect. The second joint is about as long as wide. In the 

 type the pale frontal margin is wide, the prothorax is black with narrow pale 

 margin ; elytra dull, not tuberculate, pale margin continuous around the apex ; 

 venter entirely pale ; legs in great part blackish. The elytral vittje are variable 

 in width and the head, thorax, under surface and legs vary through intermediate 

 stages to entirely pale. 



I have seen but few specimens and all from the same region — the 

 lower Colorado River. Professor Wickham has taken the species at 

 Needles and Yuma on the California side of the river. 



C. vittatus Say. Jour. Acad. Nat. Sci. Phila., Ill, 1823, p. 184. 



This species varies greatly in the minor details of form, color and 

 sculpture and shows a marked tendency to develop races which are to 

 a considerable extent geographical. The thoracic spot may be large 

 or small, is often divided into two smaller ones and is not infre- 

 quently entirely wanting. The elytral vittse are fairly constant and 

 in my experience never completely interrupted, the lateral, apical and 

 sutural pale margins continuous. The basal antennal joint is sub- 

 triangular, about y^ longer than wide, not impressed posteriorly, 

 more or less flattened anteriorly; second joint narrower than usual, 

 as long as wide, appendix short. In specimens from the North- 

 eastern States the puncuation is relatively coarse, the surface shining 

 throughout, antennas of both sexes more or less infuscate, legs almost 

 entirely black. In specimens from the arid southwest the size is 

 somewhat larger, the punctuation finer, surface of elytra less shining 

 or even quite dull, antennae of ^ entirely pale, legs more or less pale. 

 In Dakota, Montana, Colorado and some parts of Texas and Arizona 

 perfectly intermediate forms prevail and I have found it practically 

 impossible to define well-limited varieties. 



Including its varietal or racial forms vittatus is very widely dis- 

 persed, occurring froin Quebec to Saskatchewan and Arizona. It is 

 not equally common and perhaps not continuous throughout its range. 



