On Aquatic Carnivorous Coleoptcra or Dijtiscida;. 285 



but one individual which is a female ; and has the structure of the last ventral 

 segment much as in the same sex of M. marginalis, the front and middle tarsi on 

 the other hand are more slender. 



BrazU, (Weliiicke). 60G. 



89. Macrovatellus ventralis, n. sp. — Oblongo-ovalis, parce pubescens, vix opacus, 

 crebre punctatus, fuscus, uiarginibus minus distincte rufescentibus, antennis pedi- 

 busquerufo-obscuris ; capite crebre a?qualiter punctato ; prothorace valde transverse, 

 lateribus sinuatis, angulis posterioribus acutis, parce punctato, ante basin obsolete 

 transversim depresso ; elytris elongatis, deplanatis, minus fortiter et dense punctatis, 

 parcius pubescentibus ; coxis posterioribus sat crebre fortiter punctatis. Long. 6i 

 m.ni., lat. 3^ m.m. 



The elongate and flattened elytra, the more obscure colour, tlie less dense and 

 less scabrous punctuation of the elytra, and the different punctuation of the head 

 characterize this species ; the punctures on the head show no diminution on the 

 front part. The individual described has lost its tarsi, but is, I think, a male ; the 

 front femora in the middle are subtuberculate, and near to the prominent part are 

 densely ciliate (these characters exist to a slight extent in the other species but 

 are more distinct in the present one) ; the ajjical venti'al segment is remarkably 

 short. 



Brazil, (Wehncke). 607. 



I. 12.— Genus VATELLUS. 



Ventral sutures extremely deep ; anterior tarsi extremely elongate and slender. 

 The only s^Decies known is very rare in collections. 



90. Hydroporus tarsatus. Lap. Valellus tarsatus M.C. — Oblongo-ovalis, sub- 

 tiliter sed evidenter pubescens, dense fortiterque punctatus, opacus, niger, antennis 

 pedibusque piceis, femoribus dilutioribus, prothorace transverse, elytris multo 

 angustiore, lateribus sinuatis, angulis posterioribus acutis, sat fortiter punctato ; 

 elytris densius fortiterque punctatis, scabris ; coxis posterioribus fortiter profundeque 

 punctatis ; abdomine sat fortiter punctato, suturis profundis ; tarsis a.nterioribus, 

 elongatis, angustis, articulo 3° quam 2° vix angustiore. Long. 5, lat. 21 m.m. 



The tarsi differ but little in the sexes, but they are not quite so slender in the 

 male as in the female ; the hind trochanters in the male are peculiarly globular and 

 swollen. 



Cayeune. 443. 



2P2 



