BEVISION OF LISTROCHELUS — SAYLOR 83 



impimctate. Antennal club equal to funicle. Thorax with fine, 

 dense, and regularly placed punctures; lateral margin coarsely crenate, 

 with long cilia; disk with a small, longitudinal impunctate area at 

 middle. Elytra with fine and dense punctures and apparently much 

 smaller punctures intermixed, the hairs small to minute on disk, a 

 little longer near and at the sides; striae, except sutural, obsolete. 

 Pygidium strongly convex, with fine and sparse punctures, the hairs 

 short and erect ; apical part highly polished and less densely punctate, 

 basal half pruinose or subpruinose. Abdomen flattened and slightly 

 concave at middle, with dense, short erect hairs; sixth segment 

 coarsely and rugosely punctate, with long erect hairs, with a rather 

 deep median longitudinal sulcus, the area each side of middle with an 

 oblique raised ridge on each side. All claws strongly pectinate along 

 a double margin, without larger intermixed teeth. 



Female. — Antennal club shorter than funicle. Base of clypeus 

 somewhat tumid. Pygidium convex, densely pruinose in basal three- 

 fourths, with fine, sparse punctures, and short, erect hair; apex with a 

 strong, raised, and smooth V-shaped area. Abdomen slightly convex, 

 pohshed, with fine, sparse, setigerous punctures; sixth segment as long 

 as preceding but more densely and coarsely punctate and the hairs 

 longer and more coarse. All claws serrate or subpectinate along a 

 double margin, and each claw with a large, triangular median tooth. 

 Otherwise as in male. 



Length. — 17-20 mm. Width. — 7.5-8 mm. 



Types. — Holotype and allotj^pe are from the Huachuca Moun- 

 tains, Carr Canyon, Arizona, collected by M. A. Cazier on June 14, 

 1936 (Saylor collection) and are deposited in the United States 

 National Museum (No. 53761). 



Paraiypes. — Males, 14; females, 12. Arizona: Huachuca Moun- 

 tains, July [U.S.N.M.], July 14 (Cazier) [Saylor]; June (Duncan) 

 [Saylor] and July 8 (Beamer) [Snow Museum] ; Santa Kita Mountains, 

 July 24 (L. Anderson) [Snow Museum] ; Chiricahua Mountains, June 

 (Wickham) [U.S.N.M. and Saylor]; Kamsey Canyon, Huachuca 

 Mountains (Cochise County) July [Saylor], Mexico: Ciudad Juarez, 

 Chihuahua [Saylor]. 



Remarks. — While closely allied to L. disparilis Horn, L. huachuca is 

 readily separated by the more elongate form and pruinosity of the 

 dorsal surface (elytra), as well as by other structural and genitalic 

 characters as shown in the keys. The form of the female pygidium 

 in the three allied species (L. disparilis, L. huachuca, and L. chapini) is 

 but slightly variable within each species and is of much assistance in 

 separating specimens of this sex from one another. 



219855—40 4 



