504 On Aquatic Carnivorous Coleoptera or Dytiscde. 
supra castaneus, antennis tibiisque anterioribus rufis, femoribus medio pedibusque 
posterioribus piceis. Long. 9, lat. 54 m.m. 
The 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 
hairs, 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, Northern Africa ; (South of England ; Alsatia ; 
France, basin of the Seine ; Pyrenees, Spain, Portugal, Italy, Tangier). 784. 
Group 5. 
Prosternal process broad and polished ; its margin just behind the coxe very broad 
and dilated, in the posterior half excessively fine. 
Three New World species. 
689. Colymbetes stagninus, Say, Agabus stagninus, M.C.—Ovalis, minus con- 
vexus, niger, antennis rufis, pedibus piceis, elytris ante apicem vitta sublaterali 
elongata testacea ; vel nitidus (¢) densiusque punctato-reticulatus, vel subnitidus (9) 
densiusque minus obsolete reticulatus ; prothorace magno. Long. 10, lat. 5$ 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 the 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. 
690. Agabus semivittatus, Lec., M.C.—¢ Ovalis, convexus, nitidus, niger, antennis 
rufis, pedibus obscure rufis, elytris ante apicem vitta sublaterali elongata testacea 
sat distincta ; elytris subtilissime punctulatis haud perspicue reticulatis ; prothorace 
magno. Long. 9, lat. 54 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 
