StupliijUnidcjc of tlie Amazon Valley. 403 



race transverso, dorso obsolete bi-impresso. Long. corp. 



Antennae short, the five basal joints yellow, the others 

 black ; 2nd joint short and stout, 3rd very slender, 4th and 

 5th similar to one another, very small ; 6 — 10 strongly trans- 

 verse, the 6th much broader than the preceding ones, 7th 

 bi'oader than 6th, and 8th than the 7fh ; 8 — 10 very similar 

 to one another, 11th short. Palpi yellow. Head greatly 

 narroAver than the thorax, only half as broad as the elytra ; 

 black, indistinctly but not altogether finely punctured, 

 almost dull ; ocelli small but distinct. Thorax about tAvice 

 as broad as long, distinctly narrower than the elytra ; the 

 sides rounded and rather more narrowed in fi-ont than 

 behind ; on the middle are two very obsolete, large im- 

 pressions ; its pimctuation is obsolete, but it is scarcely 

 shining. Elvtra twice as long as the thorax, their outer 

 hind angle rounded, the sutural one almost rectangular ; 

 they are rather closely but quite indistinctly punctured, 

 the punctuation at the apex becoming even finer and more 

 indistinct than at the base ; they are black and almost 

 opaque. Hind body black, dull, its punctuation exces- 

 sively fine, the lateral margins broad. The legs are yellow, 

 but somewhat infuscate ; they are short and slender ; the 

 tarsi are very short ; the metasternum has a deep channel 

 on its hinder part. 



Two individuals of this species were found by Dr. Trail 

 on the 5th November, 1874, but he has sent me no special 

 locality. 



PlESTUS. 



The insects of this genus are confined to the warm 

 parts of the New World, though it must not be forgotten 

 that the North American and European genus Siagonium 

 approaches them very closely. The genus comprises 

 about eighteen described species, and I here add five 

 to that number. Of these five, tAvo — viz., P. validus and 

 P. frontalis — belong to the group of large species having 

 the head armed Avith horns, and the mandibles much 

 developed; P. rectus belongs to the P. minutus, Er., 

 group ; while P. rugosus and P. aper have as their only 

 described near ally, P. angularis, Fauv. 



The species of the genus have, many of them, an ap- 

 parently wide range in South America, and their dis- 

 crimination from one another in a satisfactory manner 



DD 2 



