1 62 MEMOIRS ON THE COLEOPTERA 



four-fifths the maximum width and but very little narrower than the 

 apex; surface convexly declivous almost to the lateral reflexed bead from 

 apex to base, the latero-subbasal impressions short and very feeble, the 

 transverse impression very feeble, the anterior obsolete, the median 

 stria distinct; elytra oval, with broadly arcuate sides and obtuse apex, 

 distinctly wider behind the middle than at base, nearly one-half wider than 

 the prothorax and barely one-half longer than wide; striae very fine, not 

 at all punctulate, the three foveae distinct, the intervals flat; hind tarsi 

 much shorter than the tibiae, the pectination of the claws short but fine. 

 Length (9) 8.5 mm.; width 3.2 mm. Mexico (Sierra Madre Mts., of 

 Chihuahua), C. H. T. Townsend. 



There is no species closely allied to this, with which it can be 

 compared. The mentum tooth is trapezoidal, flat, broadly and 

 very faintly impressed medially except toward base, the lobes of the 

 apex rather acutely angulate and separated by a deep angular 

 emargination. 



Rhadine Lee. 



This genus should be considered valid, not so much because of 

 modifications of special organs, as on account of its general habitus, 

 in which feature it is sharply delimited from Platynns. I was 

 abandoned by LeConte, for the reason that there seemed to be no 

 structural character pertaining to special parts or organs that dis- 

 tinguishes it abruptly from Platynus, as for example, the dorsal 

 modifications of the anterior tarsi ; the occasional grooving of this sur- 

 face is of no generic significance whatever, as it becomes completely 

 lost in species otherwise closely allied to those possessing it, and, 

 in one before me, it is only partially present on the first joint. 

 The slender body, with narrow and generally much elongated pro- 

 thorax, flattened upper surface and long slender legs, give the group 

 a very peculiar appearance among the Platynids; in addition to this, 

 the third antennal joint, although variable, appears to be somewhat 

 constantly longer in a relative sense. The species are numerous 

 but local in range and are not abundant individually; they are 

 almost peculiar to the southwestern faunal regions of North America 

 and those now in my collection, mostly represented by single 

 examples, may be identified as follows: 



Larger species always over 10 mm. in length 2 



Small species, always much less than 10 mm. in length 8 



2 Elytral striae with distinct and comparatively coarse punctures, the 

 intervals more or less convex; pronotum with a few scattered punc- 

 tures toward the sides 3 



