EEVISIOX OF LISTKOCHELUS — SAYLOR 79 



conspicuous; clypeal apex sub truncate, rather strongly reflexed, angles 

 rather broadly but not suddenly rounded. Antenna 10-segmented 

 (rarely 9-segrnented), the club about subequal to fmiicle. Thorax 

 highly polished, finely, densely, and regularly punctured; sides with 

 long cilia, and crenulate in front of the median dilation only; hind 

 angles angularly rounded, front angles slightly rounded; front and 

 basal margmal lines strongly indicated. Elytra punctured as thorax 

 but less densely so, with moderately long and suberect hairs; costae, 

 except sutural, obsolete. Pygidium very convex, polished, sparsely 

 and finely punctate, with very short and erect hair. Abdomen flat- 

 tened, and moderately densely, but finely, subgranulate at center; 

 fifth segment equal in length to fourth ; sixth three times the length of 

 the fifth, raised rather conspicuously at each side into a prominence 

 that forms the side of the very wide and sharp transverse carina, the 

 latter slightly curved and extending practically from side to side of 

 the segment, the remainder of the sixth segment flattened, polished, 

 and very finely, sparsely punctate. All claws subpectinate along two 

 margms, the front outer claws alone having a larger triangular tooth 

 near the apex. Hind trochanter strongly prolonged beliind the femur 

 into a spinelike projection (fig. 4, a). First segment of hind tarsi longer 

 than the second, all hind tarsal segments except the last with very 

 dense hair below. 



Female. — More robust, thorax more rufopiceous. Antenna three- 

 fourths the length of the funicle. Pygidium flattened to slightly con- 

 cave at center, pruinose and densely, finely punctate in basal two- 

 thirds and highly polished and more coarsely punctate apically; sur- 

 face with dense, erect, moderately long hairs; disk just before apex 

 faintly tumid. Claws serrate along two (high power, 20 X) margins, 

 with a moderately large triangular tooth at the center of each, the 

 inner claw of the hind tarsi, however, with the median larger tooth 

 absent. Hind trochanter hardly produced. Otherwise similar to 

 male. 



Length.-— n. 5-17 mm. Width.— Q-7 mm. 



Type. — From "Arizona," in the Horn collection. 



Specimens examined: Males, 26; females, 11. Arizona: Seen from 

 a rather limited area in the southeastern part of the State, embracing 

 Graham (Oracle), Pima (Tucson), Cochise, and Santa Cruz (Nogales) 

 Counties; July and August. 



Remarks. — Easily distinguished in the male sex by the strongly 

 produced hind trochanters and the abdominal armature, which have 

 no counterpart in the described species of the genus. This species, 

 together with L. scoparia LeConte, L. geniryi Saylor, and L. terminalis 

 Saylor, forms a group of the genus having in the males oddly formed 

 fifth abdominal segments and densely pilose hind tarsal segments; in 



