91 



recognize in these descriptions a spccies which I met with sparingly 

 on the Upper Amazons and have also received from Cayenne, All 

 my specimens however are ,,rubro-aeneus", only on the front and 

 sides of the prothorax and on the pygidium ; the sides and apcx of 

 the elytra are also sometinies coppery. The species probably va- 

 ries greatly in colour. Il is of the sanie broad form as P. festi- 

 vus, but much snialler (7 — 8 lin.). Very feeble males are without 

 cephalic hörn, but have a bituberculate frontal cariua. The 

 prothorax has a broad fovea near its anterior niargin, having a tu- 

 bercle on each side', which structure distinguishes them at once 

 from the J whicli has the usual short curved carina. The cephalic 

 hörn of the fully-developed J differs from that of all the allied 

 species being straight, dilated in the niiddle and narrowed towards 

 the apex. 



11. Phanaeus Sileniis Ca stein. 



Oxysternon Silenus Gast. Hist, nat. Col. II. p. 82. 



The expression: ,,tete ayant une carene transversale bituber- 

 culee dans les ?" shows that the author mistook undeveloped males 

 for females. Fully developed males appear to be very rare; al- 

 though I frequently took the species on the Amazons I never met 

 with these males. I have since received one from Bolivia. The 

 species has the narrower form of P. floriyer. Cephalic hörn of 

 the J long, perfectly straight and truncated at the apex, Undeve- 

 loped males have a short bituberculate carina on the vertex, the 

 same carina being trituberculate in the ? . Colour extremely vari- 

 able. Thorax brilliant coppery, green or light blue; elytra gene- 

 rally black, with coppery margins. 



