72 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii4 



Remarks. — Variation in 0. knulli, as in 0. alluvius, occurs mostly 

 in size and color. Males vary from 4.0 to 5.5 mm, in length and from 

 2.5 to 3.2 mm. in width; females vary from 3.4 to 5.9 mm. in length 

 and from 2.3 to 3.3 mm. in width. Color ranges from a dull black, 

 with an indistinct brownish cast, to a dark brown. Not infrequently 

 the elytral umbone and often the elytral apices are somewhat lighter 

 in color, so that rarely the elytra have a vague spotted appearance. 

 Some variation occiu-s in the density of punctures and elytral tuber- 

 cles, but no great variation was noted. Pronotal punctures are usu- 

 ally vaguely ringed, but frequently the outer margin is obsciu-e and 

 the punctures are in these cases identical to those of alluvius. 



Onthophagus knulli is very closely related to alluvius and slightly 

 less so to monticolus. The large distinct punctures near the posterior 

 midline of the metasternum readily distinguish knulli, and the small 

 size which averages between 4 and 5 mm. is normally less than either 

 of the related species. The lack of nonsetigerous small secondary 

 punctures on the pronotum of knulli will separate it from monticolus. 

 In addition, the distribution of knulli is apparently quite distinct from 

 that of the related forms, knulli being known only from the mountains 

 in southern Arizona. 0. knulli can be distinguished from the other 

 species of Onthophagus by its opaquely alutaceous, blackish, dorsal 

 surface, well-separated, setigerous, nonannular pronotal punctures, 

 anterior median pronotal protuberance which is always at least 

 vaguely indicated in both sexes, small size, and western range. 



The habits of knulli are similar to all the general dung feeders. 

 Specimens occur not only under cow and horse dung, but are common 

 at carrion of various vertebrates. Most of the specimens collected 

 by us were taken in the lower elevations of the Chiricahua Mountains 

 between 5000 and 6000 ft. in areas where oaks or other broad-leafed 

 trees furnished appreciable shade. Some specimens were reared in 

 flower pots at the Southwestern Research Station of the American 

 Museum, and though not closely observed, the general developmental 

 picture did not seem to differ appreciably from that described for 

 alluvius. 



This species is named in honor of J. N. Knull, who started us on 

 this study by submitting for determination two very small specimens 

 of this species. 



Onthophagus subaeneus (Palisot de Beaiivois) 



Plate 6, Figures 54 and 55 



Copris subaeneus Palisot de Beauvois, 1811, p. 105. 



Ontho-phagus subaeneus (Palisot de Beauvois) Haldeman and LeConte, 1853, 

 p. 54.— Lacordaire, 1856, p. 109.— LeConte, 1863, p. 36.— Crotch, 1874, 

 p. 57. (See concinmis Laporte, pp. 108 and 112, for discussion of subaeneus 

 of other authors.) 



