70 LAMELLICORMA. 



sexes have two pointed horns on the vertex ; and the front edge of the clypeus in the male 

 bears an erect horn dilated at its apex, and is bidentate in the female. This strange 

 armature attains a high degree of development in the stronger males, the clypeal horn 

 being dilated at its apex in horizontal semilunar form, and the horns of the vertex 

 elongated and curved ; but all grades of degradation of this armature, as well as of the 

 anterior tumid process of the thorax, occur in the large series of individuals collected 

 by Mr. Champion, down to a form in which there is nothing except the absence of a 

 frontal carina to distinguish the male from the female. In well-developed females the 

 horns of the vertex are erect, parallel, and reach nearly to the level of the thorax, but 

 in feebler individuals they are reduced to small conical tubercles, as in the effeminate 

 males ; in neither sex are the horns connected at their base by a transverse carina. The 

 thorax, in its highest male development, is nearly vertically declivous in front, with a 

 very shallow depression on each side to receive the horn, and the central convexity 

 laterally compressed and divided into two wheals by a longitudinal furrow, the wheals 



in males of lower development and in females being reduced to the form of tubercles 

 similar to those of all forms of 0. rhinolophus. 



The colour is dark castaneous or pitchy-brown, glossy above, and more or less 



metallic-coppery or aeneous ; the legs generally dark pitchy-red, but sometimes lighter 



rufous. The elytra are much more strongly sculptured than in 0. rhinolophus, and the 



interstices are more convex. 



We figure a pair of the type-form from San Isidro. Mr. Champion met with this 



insect in rotten fruits, especially in cacao ; all the Guatemalan localities are on the 



lower parts of the Pacific slope. 



10. OnthophagUS praBCellenS. (Tab. V. figg. 8, 8 ; 8 a, side view of head and 

 thorax ; 9, $ ; 9 a, side view of head and thorax.) 

 0. rMnolopTio similis, sed differt inter alia 8 cornubus verticis obsoletis ; lsete cupreus (interdum cupreo-seneus), 



nitidus, calvus, antennis pedibusque (interdum) piceo-rufis ; tborace punctato ; elytris conspicue crenulato- 



striatis, interstitiis subconvexis, disperse punctulatis. 

 8. Caput punctulatum, clypeo versus apicem angustato, lateribus flexuosis, apice cornu erecto apice valde 



dilatato semilunari, genis dilatato-reflexis, margine rectis, vertice tuberculis duobus acutis, haud carinato. 



basi lato, apice obtuso, genis dilatatis, extus rectis, antice angulatis, vertice longe bicornuto ; tborace antice 

 declivi utrinque retuso, medio antice breviter compresso-lobato, supra snlcato. $ clypeo dentato, fronte 

 transversim carinata, vertice cornubus duobus brevibus ; tborace antice medio bituberculato. 

 Long. 7 millim. 



Hab. Amazons, Ega. 



2. Onthophagus canellinus. 



2 . Rufo-castaneus, calvus, nitidus, thoracis limbo exteriore, antennis femoribusque flavo-testaceis ; clypeo 

 triangulari bidentato, carina anteriore utrinque abbreviata, alta, cornubus duobus verticis rectis ; tborace 

 undique punctato, tuberculis anticis conico-compressis ; elytris convexis, crenato-striatis, interstitiis 

 alutaceis sat confertim punctulatis. 



Long. 8 millim. 



Hob. South America, Canelos in Ecuador. 



