Platynin^ 15 



spaced; legs and tarsi very slender. Length (9) H.3 mm.; width 2.4 

 mm. Nevada (Esmeralda Co.), — Nunenmacher. 



This very small and slender species may be placed near anthi- 

 coides, differing in the relatively more elongate third antennal 

 joint, less narrowed thoracic base, with the sharp angles slightly 

 everted, in the finer, less impressed and less punctulate elytra! 

 stri« and less sinuate apices and very much narrower interval 

 between the ninth stria and the margin; in anthicoides the elytra 

 are broadly and feebly concave laterally in a way not at all sug- 

 gested in pertenuis. From myrmecodes Horn, this species differs 

 in its slightly smaller size, in the relatively more elongate third 

 antennal joint, said to be a little longer than the fourth in myrme- 

 codes, in the slightly prominent basal angles of the prothorax and 

 apparently more distinct foveae and in the broadly rounded and 

 not acute elytral apices. 



Hemiplatynus n. gen. 



Included under this generic term are a number of Mexican species 

 hitherto classed as Platynus, but which differ materially in struc- 

 ture and appearance. The head is more or less elongate and 

 rhomboidal, the prothorax not elongate or basally constricted and 

 very widely reflexed at the sides, the elytra more or less opaque 

 and finely striate, with flat intervals and minute dorsal punctures, 

 about three in number, and without prolonged sutural angles; 

 the antennae are long and very slender, the third joint markedly 

 longer than the fourth and the legs long and slender, with the 

 external groove of the hind tarsi rather coarse and deep on the 

 first three joints. There are at hand two subgeneric groups as 

 follows : 



Prothorax large, much more than half as wide as the hind body, smooth 

 and wholly impunctate; elytra depressed, the transverse basal carina 

 making an acute and sharp angle with the reflexed side margin 

 on a line which is far outside of the median line of each elytron; 

 met-episterna barely as long as wide I {chihuahuce) 



Prothorax relatively small, more oblong, rugose and punctured, much 

 less than half as wide as the hind body; elytra more convex, the 

 basal carina forming a much more obtuse angle with the reflexed 

 sides, the angle on the median line of each elytron; met-episterna 

 elongate, nearly twice as long as wide II {umbripennis) 



