On Aquatic Carnivorous Coleoptera or Dytiscida, 491 
II. 10.—Group Acasinr. 
No stigmatic rugee; that is to-say, the semi-membranous piece bordering the 
inner edge of the first ventral plate is smooth; wing of the metasternum reaching, 
when the elytra are closed, as far outward as the margin of the epipleura. Hind 
femur on the under surface with a group of ciliz more or less developed, and situate 
quite close to the hind margin at the outer part of the femur. Side piece of the 
fourth and following ventral segments rather broad, (the length of the fourth beg 
only about twice its breadth). 
The character by which a member of this group may be most readily recognised 
is the group of ciliz at the angle of the hind femur. Ten genera are included in 
the Agabini and they may readily be discriminated by the following table: 
if ( Palpi with their terminal joint dilated; that of the HYDROTRUPES. 
labial very large and subquadrate. (Vide p. 492.) 
Coxal lines very deep and \ AGABINUS. 
nearly straight, (Vide p. 548,) 
wedge-shaped, 
never linear, 
variable in size but 
always distinctly 
i AGABUS. 
| Coxal lines fine, sinuate. (Vide p. 493.) 
Wing of metasternum 
Epipleurz continuing rather broad } PLATAMBUS. 
after the middle of wing-case. ? (Vide p. 548.) 
| 
| 
) Hind coxa very large. 
R 
stout; thorax slightly 
margined at sides ; upper 
ILYBIOSOMA. 
Swimming legs short my | 
(Vide p. 537.) 
ny 
Palpi with the terminal joints undilated. 
ye I 
a rface convex; size large 
2 m.m. long. \ 
- Coxal lines present, distinct, 
"| 
| 
; Swimming legs rather slen- 
der ; hors margined at PLATYNEOTES. 
gfidles ¢ upper eerie (Vide p. 538.) 
raaviinare flat ; size i 
small (8 m.m. long. 
portion of the hind coxa. 
quite narrow. 
LEURONECTES. 
(Vide p. 546.) 
Thorax not margined at 
sides. 
op nh 
linear, deflexed on the outside of front 
Wing of metasternum quite slender and 
of their joints but little lobed or produced on the outer side, 
Epipleure after middle of length 
Posterior tarsi with their claws nearly or quite equal, and with the hind margins 
Ee (Vide p. 547.) 
Taelicy 
@ 2 |. METRONECTES 
8 ra Hind coxa small. (Vide p. 492.) 
Posterior tarsi with their claws decidedly unequal ; and with 
the lower part of the hind margin of their joints, on the outer 
face, produced or lobed. 
ILYBIUS. 
(Vide p. 550.) 
J 
J 
{ AGAMETRUS, 
TRANS. ROY. DUB. SOC., N.S., VOL, II. 38 
