COLEOPTERA. 
47 
southern parts of Brazil to Para (and Cayenne?) It is the largest species, 
reaching to 12£ lines in length, including the head and rostrum, but one 
of the narrowest in proportion to its length, and the most elongate in its 
various organs. When looked at from the side it is the flattest in the body 
and elytra, and (except Pt. depressus, Jekel) it maybe regarded as the most 
widely and strongly depressed on the disc. 
Head elongate behind the eyes, evidently longer than wide, scarcely 
convex lengthwise, the most depressed of the genus. Rostrum very long in 
both sexes, being in the male a third and in the female a fourth longer 
than the basal breadth, slightly narrower than the head. Antennce varying 
in length, according to the size of the specimens of the male, with the in¬ 
termediate development between the two extremes above described; those 
of the female, as far as I have observed, scarcely vary. 
Thorax (like that of Pt. obsoletus , Jekel) the most elongate of the 
genus, in the male one-sixth and in the female one-eighth longer than 
broad, as widely and deeply depressed on the disc as in Pt. depressus , and 
less thickly rounded at the sides and beneath than in many of the species; 
the sides slightly strangulate at the apex, slightly and roundly dilated to 
the posterior carina, thence obliquely narrowed to the base; posterior carina 
widely interrupted in the middle (in proportion), concavely curved at each 
side of that interruption, thence rather obliquely directed upwards to the 
sides, where it is semicircularly rounded, afterwards subsinuately directed 
towards the apex, where it is lost in the two obsolete transverse wrinkles 
beneath the apex, the uppermost of which is obsoletely continued (like a 
margination) upwards and downwards. 
Scutellum more or less transverse, generally at least twice as wide as 
long, sometimes only one-half wider, but in this last case it is one of the 
most transverse in the genus. 
Elytra broadly depressed on the disc, but less deeply than in Pt. de¬ 
pressus , the depression reaching the fourth stria ; base of each very obtusely 
rounded, conjointly emarginate in the middle, widely rounded at the sides, 
where the shoulders are oblique and slightly callose ; its margination forms 
a sort of fold, wider in the middle. The sides are, in the most developed 
males, evidently most narrowed towards the apex (as in Pt. nebulosus , 01., 
and Pt. depressus , Jekel) of any of the species, and those of the small males 
and of the females are as much narrowed as in the males of the other 
species. They are certainly the most elongate in the genus, being nearly 
twice and a half as long as broad in the middle: they are also less convex 
