Hydrometride. 147 
taceous in front, black behind; sides slightly sinuate ; 
posterior angles rounded and produced; base slightly 
sinuate ; disc with two small fovex anteriorly ; scutellum 
black, more or less pale in the centre; elytra with the 
nerves of the corium very strong, pale between them; 
clavus membranous, white; membrane, when present, 
white, and without nerves; legs testaceous ; abdomen pale, 
beneath clothed with deuse white pubescence. 
L. 33 wm. 
Burton-on-Trent, Woking Canal; rare. 
HYDROMETRINA. 
HYDROMETRA, Jair. 
This genus is so peculiar in form that it cannot be 
confounded with any other; its habit also of walking 
slowly along the surface of the water is, I believe, peculiar 
to itself. There is only, so far as I know, one Palearctic 
species, 
Very elongate linear. Head very long, longer than the 
entire thorax, widest in front, at the antenniferous tubercles ; 
eyes far remote from the pronotum; ocelli absent; face 
horizontal ; antennz slender, inserted near the apex of the 
head, first joint reaching slightly beyond the apex of the 
head ; rostrum three-jointed, scarcely as long as the head; 
pronotum nearly parallel-sided, more than twice as long as 
wide; scutellum hidden; elytra in developed specimens in 
one piece, nearly as long as the abdomen, in undeveloped 
specimens short and subtruncate ; abdomen nearly parallel- 
sided ; genital segments long in the d, two visible above, 
the first produced above over the second in a point, beneath 
with two small tubercles; apical abdominal segment also 
with two raised ridge-like tubercles; ? with the genital 
segments shorter, but with the projecting point of the first 
segment longer, reaching beyond the apex of the second ; 
L 2 
