74 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 89 



There is considerable variation in the male genitalia, each type of 

 small variation being limited, however, to one general region (see 

 fig. 5, i-n); since these variations are only in degree and since there 

 appears to be no other internal or external differences, I believe this 

 aggregation of specimens is better treated as a single variable species. 



PHYLLOPHAGA (LISTROCHELUS) DENSICOLLIS (LeConte) 



Figures 5, e, f; 13, c, d 



Ldstrochelus densicollis LeConte, Smithsonian Misc. Coll., vol. 6, No. 167, p. 77, 

 1863.— Horn, Trans. Amer. Ent. Soc, vol. 7, p. 143, 1878. 



Male. — Elongate, wider behind, elytra rather dull brown and 

 moderately densely pruinose; thorax and head rufopiceous, moderately 

 shining. Head glabrous, coarsely, rugosely, and densely punctate; 

 transverse carina of vertex rather noticeable; clypeus very tumid at 

 center of base, the tumosity densely and coarsely punctured; apex of 

 clypeus subtruncate, very slightly emarginate, the angles narrowly 

 rounded, margins but little reflexed; front ver}^ coarsel}^ and closely 

 punctate. Antenna 10-segmented, the club very shghtly longer than 

 the funicle. Prothorax densely, subrugosely, and (in front) coarsely 

 punctured, lateral margins with long cilia, the margin in front of the 

 median lateral dilation coarsely crenate, that behind the dilation 

 entire; hind angles subangularly rounded, the front angles noticeably 

 rounded ; front and basal margins strong and entire. Elytra pimctured 

 as thorax, with short, inconspicuous, j^ellow hairs in the punctures; 

 striae, except the sutural, hardly obvious. Pygidium very convex, 

 strongly shining, with fine, moderate-sized, and dense punctures 

 and with short, scattered, and suberect hau*; apex subrounded. 

 Abdomen flattened at middle, polished, sparsely pilose; fifth segment 

 shorter than fourth, plane; sLxth segment rather large, strongly convex, 

 and with a very large and broad, moderately deep fovea in the middle, 

 the surface with sparse, moderately long, and erect hair. All claws 

 pectinate along a single margin, the pectinations large and of uniform 

 size; first segment of hind tarsus much shorter than the second, 

 hind tarsus scarcely longer than its tibia. Genitalia as in figure 5, 

 ej. 



Female. — Antennal club three-fourths the length of the funicle; 

 elytra markedly pruinose. Pygidium convex, moderately densely 

 punctate, with short erect hairs; disk pruinose in basal half and 

 poHshed in apical portion, the apical margin slightly explanate (the 

 disk in the apical half is more densely punctate, and either tumid or 

 faintly and longitudinally impressed at the center). Abdomen 

 polished, shghtly convex; sixth segment slightly convex, moderately 

 densely and setigerously punctate. All claws subpectinate along a 

 single margin, with a large triangular tooth beyond the middle (i. e., 



