330 Flemiptera-Fleteroptera. 
is considered by Messrs. Douglas and Scott to represent the 
embolium); legs simple, tarsi two-jointed, posterior pair 
longer than the others, but not natatorial as in Notonecta. 
P. minutissima, Fal.—Ochreous, very strongly punc- 
tured; head with a dark central line, elytra sometimes with 
a transverse band across the centre, and the apex darker. 
L. 24 mm. 
Generally distributed. 
CORIXIDA. 
Subelongate or elongate oval, somewhat flat. Head 
viewed from above, very transverse, wider than the pro- 
notum, very concave posteriorly, so as to cover and 
embrace the front of the pronotum, eyes large, triangular, 
with few exceptions, their posterior margins straight, 
nearly parallel to and touching the posterior margin of the 
head, looked at from above, their anterior margins form a 
continuous curve with the front of the head, face elongate, 
rounded and vertical in front, then produced triangularly 
with a subventral aspect, antennze three- to four-jointed, 
no distinct rostrum, but the underside of the head, in front 
of the occipital foramen, is divided by a transverse suture 
from the apical portion, which is rounded in front, and 
from its margin projects a series of long yellow hairs; 
pronotum more or less triangular, the sides being ex- 
ceedingly short, and the base generally produced and 
angulated; scutelluam present, or wanting; elytra with a 
more or less distinct membrane, and a deep sulcus along 
the lateral margin ; anterior tibize very short, tarsi or pale 
variable in form, one-jointed, intermediate legs elongate, 
tarsi one-jointed, terminating in two long narrow claws, 
posterior tarsi flattened and oar-shaped, two-jointed, their 
sides clothed with long hairs; pleurz of the sterna dis- 
tinct, mesosternum with a lateral piece beyond the pleura 
