XYLOEYCTES.— MEQACEBAS. 325 



Chiriqui above described, but differing in the much more slanting truncature of the 

 fore part of the thorax and the absence of median prominence. Slight as their 

 peculiarities are they cannot be referred as varieties to any of the other described 

 species. 



The species is labelled X. teuthras, Candeze, in the Salle collection. 



7. Xyloryctes thestalns. (Tab. XVIII. figg. 25, 25 a, s .) 



Kobustus, X. tdepho lathis oblongus, piceo- vel castaneo-niger ; elytris subtiliter punctulato-striatis, interstitns 

 convexis, stria suturali punctata distincta sed medio parum impressa ; pygidio disperse punctate 



g major. Cornu capitis altum, subrecurvum, apice postice nodosum ; thorax antice valde oblique declivis nee 

 medio concavus, lobo mediano longe post medium oblique ascendenti, apice lato et plerumque emarginato. 



Long. 32-37 millim. S . 



Hab. Mexico, near the city (Flolir, Hoge). 



Numerous examples, differing but little in development, and all distinguished from 

 X. telephus, apart from the presence of a sutural stria, by the very different form of the 

 thoracic truncature, and the position of the central lobe or short horn projecting from 

 its upper margin ; this latter in X. teleplws and in other species rises much before the 

 middle of the thorax, and in X. thestalus considerably behind the middle, with the 

 correspondingly oblique truncature plane, instead of concave, in the centre. 



Certain female examples from the same locality may belong to this species ; they do 

 not, however, differ from the corresponding sex of X. furcatus. They are of large size 

 (34 millim.), and have a distinct punctured sutural stria, with other stria? on the elytra 

 indicated by convex interstices as in the male. 



MEGACERAS. 



Megaceras, Hope, Col. Man. i. p. 82, t. 1. fig. 1 (1837) ; Burmeister, Handb. der Ent. v. p. 221 ; 

 Lacordaire, Gen. Col. iii. p. 435. 



Seven species of this fine genus have been described, all from Tropical South America ; 

 one of them is here recorded for the first time as occurring north of the isthmus. 



l. Megaceras philoctetes. (Tab. XIX. figg. 6, 6 a, s var.) 



Scarabaus philoctetes, Oliv. Ent. i. 3, p. 16, t. 14. fig. 125 \ 



Hab. Costa Rica {Salle, Van Patten), Cache (Bogers) ; Panama, Bugaba, Volcan de 

 Chiriqui 4000 to 6000 feet (Champion).— South America, Surinam, Guiana, Brazil 1 . 



The very numerous Central- American specimens differ from the many typical examples 

 from Surinam and the Amazons with which I have compared them sufficiently to be 

 distinguished as a local form : — 



Yar. M. septentrionis. Brevior, piceo-niger vel castaneus ; clypeo acute bidentato ; thorace brevi, lateribus 



medio valde rotundatis, angulis posticis obtusis fere rotundatis, in S interdum (raro) subrectis. 

 .<$ . Cornu capitis apice latum emarginatum, interdum subacutum, postice prope apicem obtusissime tuberculatum 



