On Aquatic Carnivorous Coleoptera or Dytiscide. 647 
Mas, nitidus, elytris versus apicem crebrius subtiliusque punctatis. 
Fem., subopaca, prothorace utrinque versus latera subtilissime punctato, elytris 
ad apicem crebrius subtiliter punctatis, punctis sublateralibus majoribus conspicuis. 
In the male of this species the small palettes of the front tarsi remain quite 
rudimentary and undeveloped, being no larger than those of the intermediate feet. 
The colour of the under surface in this species is peculiar; the prosternum is 
testaceous with its process black, the breast is black with a large dash of yellow 
on the front part of the hind coxz, while the ventral segments are yellowish, 
marked with black especially at the sides and apex: the yellow lateral band of the 
elytra is broad, and is divided at the apex by a large space into two parts, the 
anterior of which is quite distinct. I have not seen enough specimens to know 
whether there is much variation in the species. 
The species has undoubtedly much in common with D. latissimus, particularly 
the labrum, the nature of the punctuation, the form of the yellow band at the apex 
of the elytra, and the condition of the clothing of the male tarsi ; it departs, however, 
widely therefrom by the undilated margins of the wing-cases, the form of the coxal 
processes, and the unsulcate elytra in the female. In certain respects 1t resembles 
D. verticalis, and although the two at present are widely separated I should not 
be surprised if intermediate species are found to exist in North America. 
North America, (Pennsylvania, Kansas, Lake Superior, Vancouver’s Land, sec. Crotch). 953. 
III. 4.—Tribe HYDATICIDES. 
Posterior tarsi with the hind margins of their joints densely fringed with 
adpressed and flattened cilize or squamze overlapping the basal portion of the 
following joint. 
Prothorax, with a fine lateral margin, . ‘ : . . : . (sn COD) 
Prothorax without lateral margin, episternal suture curvilinear, spurs of | THERMONECTINI. 
hind tarsi emarginate at apex. f (Vide p. 672.) 
Prothorax without lateral margin, episternal suture rectilinear, spurs of ‘ HiypATICcINI. 
hind tarsi accuminate at apex. (Vide below.) 
~ 
II. 13.—Group Hyparicint. 
Metathoracic episternum large, the suture between it and the wing of the 
metasternum rectilinear, spurs of posterior tibize quite acuminate. 
Claws of posterior feet nearly equal, , { P Vide p. a8. . 
Claws of posterior feet very unequal, : : 0 5 . . | (ie, = ronan 
