coxal cavities 
destitute of 
| 
320 
{ Ventral seg-) 
| ment sol- 
dered to 
| | border of eas 
posterior 
| coxe. 
| { Hind coxal cavi-) 
| ties separated, 
| not all protect- | 
| ed by the ad- 
pressed  coxal 
| processes. 
Posterior | H 
| First ventral 
Scutellum invisible. 
coxal exci- 4 
sion, and segment] 47. ; 
: © Hind coxal cavi- 
extra-rimal free, nots (ee eee ae 
lobe. soldered to : se aie 
quite contigu- 
the coxe. 
ous, being pro- 
longed TEN TENS 
above the coxal 
processes, and 
so protected by | 
the latter. 
Scutellum | 
exposed. 
( Mesosternum 
—— 
On Aquatic Carnivorous Coleoptera or Dytiscide. 
BIDESSINI. 
(Vide p. 336.) 
ee HYPHYDRINI. 
(Vide p. 370.) 
placed | 
nearly on the same 
plane as the meta- 
sternum and there- 
fore much exposed 
between this and the 
prothorax ; its an | 
meron very narrow, 
sublinear, and indis- 
tinct. J 
STERNOPRISCUS. 
(Vide p. 384.) 
Mesosternum placed) 
at an angle with the 
metasternum and 
thusmuch concealed; 
its epimeron — tri- 
angular and distinct. J 
HYyDROPORINI. 
(Vide p. 389.) 
CELINA. 
(Vide p. 487.) 
II. 6.—Group Hyprovarint. 
Prosternal process almost triangular, its posterior margin forming the base of the 
triangle, hind coxal cavities not contiguous, with broad coxal processes incised behind 
by a distinct coxal excision, external to which is a free, prominent, portion of the 
process (=extra-rimal lobe.) 
There are only two genera included in this family ; they may be readily dis- 
tinguished as below, one is an autogenus, the other is rich in species. 
in the transverse direction; labrum 
Coxal excision longer in the longitudinal than 
Numerous species. 
visibly exserted. 
Coxal excision shorter in the longitudinal than ) 
in the transverse direction; only the 
fringes of the labrum visible. A single 
species. ) 
HYDROVATUS. 
(Vide p. 321.) 
QUEDA. 
(Vide p. 336.) 
