604 On Aquatic Carnivorous Coleoptera or DytiscidoB. 



Bupra castaneus, antennis tibiisque anterioribus rufis, femoribus medio pedibusque 

 posterioribus piceis. Long. 9, lat. 5i m.m. 



Tlie front and middle tarsi are not very greatly thicker in the male than in the 

 female, but they are furnished beneath in the former sex with elongate glandular 

 haira, and in the same sex there are three joints of the posterior tarsus provided 

 beneath with swimming hairs. 



The species is readily distinguished by the broad form, smooth shining surface 

 unicolorous above, and by its stout legs. The prothorax is large and continuous 

 in outline with the elytra. 



Central and Southern Europe, Corsica, Sardinia, Noi-thern Africa ; (South of England ; Alsatia ; 

 France, basin of the Seine ; Pyrenees, Spain, Poi-tugal, Italy, Tangier). 784. 



Group 5. 



Prosternal process broad and polished ; its margin just behind the coxce very broad 

 and dilated, in the posterior half excessively fine. 

 Three New World species. 



689. Colymbetes stagninus, Say, Agnbus stagninus, M.C. — Ovalis, minus con- 

 vexus, niger, antennis rufis, pedibus piceis, elj^tris ante apicem vitta sublaterali 

 elongata testacea ; vel nitidus (cj) densiusque punctato-reticulatus, vel subnitidus {$) 

 densiusque minus obsolete reticulatus ; prothorace magno. Long. 10, lat. bh m.m. 



The male has the front and middle tarsi a good deal incrassate, and amply pro- 

 vided beneath with rather long hairs which bear distinct palettes, the claws of 

 the front feet are moderately long, and the anterior one has the base much dilated, 

 the posterior is rather longer than tlie anterior one, and has the base abruptly 

 thickened in a similar manner ; the terminal joints of the middle tarsi in this 

 sex are unusually elongate. The distinction in the sculpture of the sexes is very 

 marked. 



North America. (Pennsylvania). 785. 



G90. Agabus semivittatus, Lee, M.C. — S Ovalis, convexus, nitidus, niger, antennis 

 rufis, pedibus obscure rufis, elytris ante apicem vitta sublaterali elongata testacea 

 sat distincta ; elytris subtilissime punctulatis baud perspicue reticulatis ; prothorace 

 magno. Long. 9, lat. b\ m.m. 



The male has the front and middle tarsi a good deal incrassate, and amply pro- 

 vided beneath with rather long hairs which bear distinct palettes ; the claws of the 



