Genera and Species of Coleoptera. 125 



TiTHASSA [Tenebrionidse]. 



Head small, exserted, its anterior border incrassated. Antennae stout, 

 moderately long, the first and second joints scarcely thicker than the 

 third, which is longer, the remainder to the eighth short, the last three 

 foiTning an oblong, loose, compressed club. Eyes small, lateral, round. 

 Epistome and labrum naiTow, not covering the mandibles, the latter 

 broadly emarginate. Mandibles bifid at the apex ; terminal joint of the 

 palpi ovate, subacuminate, the second joint of the labial larger than 

 the third ; maxillary lobes subequal, fi-inged. Mentum subquadrate. 

 Labium rounded. Prothorax transversely subquadrate, narrower than 

 the elytra, its margins dilated. Elji;ra large, convex, broadly ovate. 

 Legs small ; coxae not approximate, the anterior cylindrical, transverse ; 

 tibiae not spm'red; tarsi pubescent beneath, the penultimate joint di- 

 lated. Prosternum pointed behind ; mesosternum depressed ; post- 

 intercoxal process triangular. 



The majority of the characters of this genus point, as it appears 

 to me, to the Diaperina3, but the differently-formed tarsi and the 

 disproportion between the prothorax and elytra forbid its union with 

 that group. At the same time, the antenn£e come nearer those of 

 Pentajilujllus " in plan " than any other heteromerous genus that I 

 am acquainted with. It seems to be a common Rio insect. 



TWiassa corynomelas. (PI. V. fig. 7.) 



T. testaceo-lutea, nitida, punctata ; ocidis, antennisque, ab articulo sexto, 



nigris. 

 Hab. Brazil (Rio). 



Dark glossy testaceoiis, or luteous-brown, iiTegularly pimctm'ed 



above, with a few very fine and extremely scattered slender hairs; 



eyes and last five joints of the antennae, including a portion of the 



sixth, which are also more hairy than the rest, black. Length 3 lines. 



Chaeiotheca [Helopidae]. 



(Dej.) Catal. des Coleopt. 



Head moderate, subquadrate. Eyes large, transverse, contiguous to the 

 prothorax. Antennae short, clavifonn, the first joint nearly concealed 

 above by the antennary orbits, the foiu' or five terminal joints com- 

 pressed and, except the last, more or less transverse. Labrum rounded 

 anteriorly. Maxillary palpi ^^^th the last joint secmiform, the labial 

 ovate, trimcate ; maxiUary lobes short, strongly ciliated. Mentiun 

 subquadrate. Labimn slightly expanded at the sides, entire and 

 ciliated in front. Prothorax ti-ansverse, nearly as broad as the elytra at 

 the base, rounded at the sides, scarcely emarginate anteriorly. El}'tra 

 elongate, their greatest breadth behind the shoulders, slightly curved 



