258 MEMOIRS ON THE COLEOPTERA 



stated to be very strong and almost equal throughout the width 

 in verticalis. 



Tribe DYNASTINI 



Not very abundant in either genera or species, this tribe includes 

 probably the largest or at least the heaviest forms of Coleoptera 

 known in the world. As a tribe it is distinguished from the Oryctini 

 principally by the form of the tarsi, which have a peculiarly long 

 and rather thick, yet filiform subglabrous appearance, with rela- 

 tively smaller and undilated basal joint, which form of tarsi is 

 shared also by the Agaocephalinae. The prothorax of the male 

 generally has a corniform process, but without excavation before 

 the process as in the Oryctini and, in the female, the pronotum is 

 invariably even in convexity, but this is not wholly distinctive of 

 the Dynastini, as in Xyloryctes, of the Oryctini, the pronotum of 

 the female is similarly unmodified and in Anoplognatho it is un- 

 modified in either sex. The mentum is rather flat, broadly suboval, 

 the labial palpi normally inserted at the sides of the narrowed ligular 

 part of the plate, the maxillary galea simple and subcylindric and 

 the mandibles strong and considerably exposed, generally bidentate. 

 Omitting some genera, such as Golofa, Podischnus and Ccelosis, 

 which latter is a Dynastid and not an Oryctid, we can separate 

 the American genera, having two lateral spines on the male pro- 

 notum in addition to the central horn, as follows: 



Post-coxal process of the prosternum large, triangular; central horn of 

 the male pronotum usually long, the lateral spines protruding from 

 the surface near the base of the horn, or from the sides of the horn 

 itself, the cephalic horn long, curving upward toward the thoracic 

 horn; mandibles sharply bidentate; anterior legs differing but little 

 in the sexes, the tibiae tridentate externally, more finely and acutely 

 in the male. [Type Scarabccus hercules Linn.] Dynastes 



Post-coxal process very feeble to obsolete, spiniform; processes of the 

 male pronotum very widely separated, at the sides of the apex; 

 maxillary galea generally more acuminate but similarly simple; 

 mandibles bidentate; prothorax with the central process small or 

 wanting, that of the head well developed, bifurcate at tip as a rule; 

 body more broadly massive 2 



2 Body very large in size; anterior legs distinctly modified sexually, the 

 anterior tibiae much longer and more arcuate in the male, the long 

 cephalic horn in the latter sex generally with a large dorsal anteriorly 

 projecting process, the prothorax without a well defined central 

 process, though obtusely tumid; pronotum with a strong polished 

 entire basal bead in both sexes. [Type Scarabccus elephas Oliv.] 



*Megasoma 



