AMERICAN COLEOPTERA. 337 



well for both sexes. The sexual characters are worthy of special 

 mention, these furnish the true basis of specific separation. The new 

 species is briefly as follows : 



M. caiiescens n. sp. — Black, clothed with fine short grey pubescence, 

 antennae, clypeuB and legs (except the posterior), yellow. Head and thorax 

 densely and finely punctured, opaque; thorax as broad at base as the elytra, 

 a fine basal impression in front of scutellura, another deeper each side. Elytra 

 coarsely and moderately densely punctured, punctures finer toward the apex. 

 Body beneath moderately densely and finely punctured and with grey pubes- 

 cence. Length .12 — . 26 inch j 3 — 6.6 mm. 



Male. — Smaller than the 9- Antennae subserrate, the joints always as long 

 as broad. Intercoxal process of abdomen with a moderately elevated tubercle, 

 the surface of which is nearly smooth. 



Female. — Larger than %, Antennae slender. No intercoxal tubercle. 

 This species is that mentioned by me as the % of concolor, (Trans. 

 Am. Ent. Soc. 1868, p. 137), having at that time but two females 

 of concolor and two males of the present, there did not seem to be 

 sufficient reason for separating them. Superficially the species greatly 

 resembles scabe?-, but may be known by the sexual characters and the 

 dark hind legs. 



Occurs from the Sierras of western Nevada, southward to Keyes- 

 ville, California. 



M. scaber Hald., Proc. Acad. 1843, p. 308. 



Male. — Antennae with third joint broadly triangular, 4 — 10 transverse, but 

 gradually less so to tip. Intercoxal process with a moderately prominent 

 umbone with jiubescent summit. 



Female. — Third joint of antennae elongate, joints 4 — 10 subserrate. 

 Occurs in the Atlantic States. 



M. concolor Lee, Proc. Acad. 1853, p. 235. 



var. flavipcnnis Horn, Trans. Am. Ent. Soc. 1868, p. 136. 



Male. — Antennae slender, third joint elongate, joints four and six shorter 

 respectively than five and seven. Intercoxal process with a large flattened 

 umbone, extending the length of the segment, finely transversely strigose like 

 a stridulating plate. 



Female. — Antennae as in the % but the joints 4 — 10 are gradually shorter, 

 eleventh elongate as usual. 



I refer to concolor a number of specimens collected by Morrison 

 in Nevada, although they are somewhat more densely punctured and 

 opaque. M. Jlavipennis Horn, under this determination is a synonym, 

 the yellow elytra counting for nothing. I have several females with 

 yellow elytra but the males and about half the females are piceous. 

 • Occurs in Colorado, New Mexico and western Nevada. 



M. quadricollis Horn, Trans. Am. Ent. Soc. 1874, p. 42. 



Male. — Third joint of antennae elongate, joints 4 — 10 as broad as long, trape- 

 zoidal. Segments 1 — 4 with a small patch of brownish pubescence at middle 

 Bear posterior border. Last ventral segment longer than the preceding, broader 



TRANS. AMER. ENT, SOC, VII. (43) OCTOBER, 1879. 



