1873.] J-"0 [Horn. 



shining, surface finely scabrous. Body beneath and legs black, moder- 

 ately shining. Length 1-1.15 inch ; 25-29 mm. 



Male. Antennae as above. Middle tibiae flattened and slightly con- 

 torted. Fifth ventral segment truncate, sixth moderately prominent and 

 feebly emarginate at tip. Last dorsal segment moderately prominent 

 and broadly rounded at tip. 



Female. Sixth ventral segment oval at tip. Antennae not seen. 



The inner spur of the hind tibae is moderately stout but acute at tip, 

 the outer spur much stouter, very obliquely truncate and laminiform at 

 tip. 



Specimens of this species said to have been collected in Texas near tbe 

 Mexican border are before me. 



0. quairimaculata, Chev. Col. Mex. Centur. I, No. 79, 1834: 



Head black, coarsely punctured, moderately shining, vertex with ru- 

 fous spot. Thorax sub-quadrate, sides in front broadly rounded, disc 

 very feebly convex, surface sparsely punctured, shining, color yellow with 

 four small black spots, the inner two larger. Elytra yellow with an 

 irregular triangular spot at basal third and a larger spot at apical third 

 on each elytron, black ; surface scabrous. Body beneath black, with 

 cinereous hairs. Length .60-.80 inch ; 15-20 mm. 



Male. Antennae with joints 4-7 stouter. Fifth ventral segment slightly 

 emarginate, sixth moderately prominent deeply emarginate with the 

 lateral processes prominent. Last dorsal segment prolonged at apex and 

 with the tips dilated. 



Female. Antennae not seen. Sixth ventral and last dorsal segments 

 oval at tip. 



The spurs of the hind tibiae are as in the preceding, but the outer is 

 less obliquely truncate and more dilated at apex. The base of thorax at 

 middle is slightly emarginate as in biguttata but in a less marked degree. 



Occurs with the preceding species. 



C. melaena, Lee. Proc. Acad. 1858, p. 76. 



Black, moderately shining. Head very sparsely punctate. Thorax 

 sub-quadrate, sides in front broadly arcuate, surface very sparsely punc- 

 tate. Elytra finely scabrous. Body beneath black, moderately shining, 

 pectus sparsely pubescent. Length .60-.80 inch ; 15-20 mm. 



Male. Antennae with joints 4-7 stouter. Fifth ventral segment truncate 

 at middle, sixth deeply emarginate and longitudinally broadly impressed, 

 lateral processes obtuse, moderately prominent. Last dorsal segment 

 acutely oval at tip. Middle tibiae flat and strongly compressed near the 

 tip. 



Female. Sixth ventral segment sub-truncate at apex. Last dorsal 

 broadly oval. Antennae moniliform gradually thicker to tip. The hinder 

 tibial spurs are similar to those of C. eucera. 



Occurs near the boundary of Arizona and Sonora. 

 A. P. s. — VOL. XIII. n 



