ONTHOPHAGUS. 67 



being porrect and conical in the former, and less advanced, rounded, and slightly in- 

 dented in the latter. It appears to me, however, doubtful if the Central- American form 

 referred to 0. curvicornis can be really the same species, as, amongst the very numerous 

 well-developed males I have examined from all parts of the region, not a single one 

 is found with the conical protuberance of the South- American type-form described 

 by Latreille ; in all the thorax has the same form as in 0. incensus. But there exists 

 another character by which the males of both the Central and the South-American 

 forms of 0. curvicornis are distinguishable from 0. incensus, viz. the absence of a 

 carina connecting the bases of the cephalic horns. In 0. incensus this carina is always 

 visible, though it is less acute in some examples than in others ; but in 0. curvicornis 

 there is no trace of a carina. 0. curvicornis is nearly always black or bluish-black, 

 with a brassy-green tinge only on the crown and near the anterior angles of the 

 thorax. 0. incensus, on the other hand, is nearly always wholly metallic above ; 

 generally dark brassy-green, but sometimes dark blue, coppery-brown, or brassy- 

 brown, with a brilliant coppery thorax. In both species the inner apical angle of 

 the male anterior tibiae is prolonged and more or less reilexed; and the elytra 

 are finely crenulate-striate, with the interstices rather thickly, irregularly, and finely 

 punctured. 



3. OnthophagUS nitidior. (Tab. V. figg. 1, <?; la, side view of head and 

 thorax.) 



0. curvicomi et 0. incenso quam maxime affinis, sed differt colore laete viridi. <$ carina posteriore nulla vel 

 obsoletissima clypeoque apice minus angustato et multo minus reflexo marginatoque ; thorace sicut in 

 0. incenso elytrisque subtiliter crenato-striatis, interstitiis sat confertim punctulatis et absque setis. 



Long. 6|-10 millim. 



Hah. Mexico, Juquila (Salle, Hoge), Yautepec (Edge). 



Specimens in the Salle collection bear the name of 0. nitidus (Sturm, MS.). 



4. OnthophagUS marginicollis. (Tab. V. figg. 2, J ; 2 a, side view of head 

 and thorax.) 



Onthophagus marginicollis, Harold, Stett. ent. Zeit. 1880, p. 31 1 . 



Hah. Guatemala (Salle), San Geronimo (Champion) ; Nicaeagua, Chontales (Belt, 

 Janson) ; Panama, Volcan de Chiriqui, David, Los Remedios. Tole (Champion). — South 

 America, Colombia \ Upper Amazons, Peru 1 . 



The head is similar in form to that of 0. curvicornis and 0. incensus, i. e. with 

 bi-cornuted vertex ; but the clypeus is obtusely rounded, and there is a deep notch at the 

 suture separating it from the rounded gense ; the head in the male is distinctly 

 bi-carinated. The thorax and elytra are usually testaceous-yellow, with the disc of the 

 former and the alternate interstices of the latter dark brassy-green. The dark colour 



KK2 



