NORTH AMERICAN COLEOPTERA. 51 



In studying Athous some time since I observed that the prosternal 

 sutures are double in discalceatus and bicolor, and that the tarsi have the 

 same structure as observed in Agriotes protractus. While considering 

 the latter as the type of Leptoschema, it is suggested that the two 

 Athous be placed in it for the present. 



The species therefore are : 



L. protractum Horn. Trans. Am. Ent. Soc. 1871, p. 317. 

 L. bicolor Lee. Trans. Am. Philos. Soc. x, p. 420. 



L. discalceatum Say, Trans. Am. Phil. Soc. vi-, p. 169 ; Lee. loe. cit. p. 427. 

 L. protractum, Horn has great resemblance in form to the figure of 

 Psiloniscus horborurus, given by Candeze, Elat. lii, pi. 1, fig. 2. 



ESIICOKYX n. g. 



Head inserted as far as the eyes which are moderately large and prominent; 

 front margined with semi-circular outline; labrum moderate, apex arcuate; man- 

 dibles prominent, acute at tip, dentate within the apex ; maxillary palpi not long, 

 the terminal joint flattened, broader at tip and obliquely truncate. Antennae 

 slender half the length of the body, eleven-jointed, very feebly serrate, joints 2-3 

 each shorter than the fourth. Lateral margin of thorax obtuse, the suture between 

 the pronotum and flanks inferior, hind angles slightly divergent; prosternum 

 broad, the sutures distant, diverging to the front, fine, not excavated, prosternum 

 arcuate at tip not acutely prolonged. Middle eoxse moderately separated, the 

 mesosternum oblique, excavated. Posterior coxal plates very narrow externally, 

 rapidly wider within, the inner angle somewhat prolonged but obtuse. Legs 

 slender, tibial spurs distinct but small ; tarsi slender, about three-fourths as long 

 as the tibife, joints 1-4 gradually decreasing in length; claws moderate in length, 

 pectinate. Scutellum cordiform, impressed. 



The characters above apply to a genus belonging to the tribe Plasto- 

 cerini of the Elateridae which is related most closely to Aphricus. The 

 present genus possesses nearly all the characters of Aphricus except that 

 the mandibles a little less prominent, while it presents the very rare char, 

 acter of pectinate claws. 



The discovery of this genus indicates a closer relationship between 

 Aphricus and the Cardiophori than has been suspected. They all have 

 the same cordiform scutellum and similar posterior coxal plates, that is, 

 narrow externally and abruptly dilated within. In the Cardiophori the 

 the margin of the front is much elevated above the base of the labrum 

 in Aphricus very nearly on the same level, and in P]niconyx intermediate 

 in structure. The mandibles are prominent in Aphricus with a wide 

 space enclosed by them ; in Eniconyx the mandibles are prominent, but 

 there is no space beyond the labrum, while in the Cardiophori the 

 mandibles do not project beyond the end of the prosternal lobe. 



