REVISION OF LISTEOCHELUS SAYLOR 91 



brous. Head with front coarsely and variolately punctate, though 

 somewhat sparsely so at the center, transverse carina of vertex 

 strongly marked; clypeus polished, sparsely punctured at sides and 

 impunctate elsewhere; apex of clypeus strongly reflexed and subtrun- 

 cate, angle broadly rounded. Antenna testaceous, club slightly longer 

 than the funicle. Thoracic disk somewhat coarsely, moderately 

 densely punctured, with a narrow^ impunctate median line; both base 

 and apex strongly margined; sides of thorax subangidarly dilated 

 behind the middle, margin coarsely crenate in front of, and finely so 

 or entire behind, the emargination; angles obtuse, not prominent. 

 Elytra coarsely, rugosely WTinkled, striae except sutural only faintly 

 indicated; disk moderately densely and finely punctate, with numerous 

 small suberect hairs; sutural striae much narrower at base and apex. 

 Pygidium strongly convex and highly polished, w4th very fine, sparse 

 punctiu-es; dis^ apparently glabrous, apex rounded. Abdomen highly 

 polished, segments wdtli moderately dense and fine punctures; sixth 

 segment slightly shorter than the fifth, flattened, entire surface cov- 

 ered with moderately dense, somewhat coarse granules and fine, erect 

 hairs. All claws pectinate along a double margin, the outer claws of 

 front and middle tarsi each with a larger tooth just before the apex, 

 hind claws pectinate to subserrate, without larger intercalated teeth. 



Female. — Antennal club shorter than funicle. Thorax slightly more 

 rufous and more densely punctate. Elytra highly pruinose. Pygi- 

 dium polished, much smaller than in the male, convex, with a sug- 

 gestion of a gibbosity each side of the m.iddle, these tw^o gibbosities 

 nearer the lateral margins than to each other; pygidial surface very 

 finely and sparsely punctate, with a few minute hairs apically. Abdo- 

 men strongly convex and very highly polished, segments 1-4 with 

 sutures nearly obsolete and the surface with a few minute hairs; fifth 

 large, declivous apically, hardly punctured; sixth subplanate, with 

 sparse erect hairs. All claws apparently subpectinate or serrate along 

 a single margin and each of the front and middle claws with a large 

 tooth just before the apex, the hind tarsi without such larger teeth. - 



Length.— l?,-\b mm. Width.— Q-Q.b mm. 



Type. — In Fall collection. 



Type locality. — ^'Baboquivari Mts. and Ajo, Arizona." 



Specimens examined. — Males, 5; females, 10. Arizona: All speci- 

 mens seen are from a rather limited locality — Pima and Cochise 

 Counties; the majority of specimens came from the Santa Rita or 

 Baboquivari Mountains, June and July. 



Remarks. — The males are readily placed by the key, and the fe- 

 males may be rather easily determined by the characteristic pygidium, 

 which is small and highly polished and convex only on the disk, as 

 well as by the characteristic shape of the abdomen in lateral view. 



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