Genera and Species of Coleoptera. 125 



Tithassa [Tenebrionidae]. 



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 

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

 Epistome and labrum narrow, 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, fringed. Mentum subquadrate. 

 Labium rounded. Prothorax transversely subquadrate, narrower than 

 the elytra, its margins dilated. Elytra large, convex, broadly ovate. 

 Legs small ; coxa3 not approximate, the anterior cylindrical, transverse ; 

 tibiae not spurred ; 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 Diaperinae, but the differently-formed tarsi and the 

 disproportion between the prothorax and elytra forbid its union with 

 that group. At the same time, the antennae come nearer those of 

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

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



Tithassa corynomelas. (PL V. fig. 7.) 



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



nigris. 

 Hob. Brazil (Rio). 



Dark glossy testaceous, or luteous-brown, irregularly punctured 



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, claviform, the first joint nearly concealed 

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

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

 anteriorly. Maxillary palpi with the last joint securiform, the labial 

 ovate, truncate ; maxillary lobes short, strongly ciliated. Mentum 

 subquadrate. Labium slightly expanded at the sides, entire and 

 ciliated in front. Prothorax transverse, nearly as broad as the elytra at 

 the base, rounded at the sides, scarcely emarginate anteriorly. Elytra 

 elongate, their greatest breadth behind the shoulders, slightly curved 



