HEMIPTERA. 35 
ones. Their body is almost cylindrical or ovoid, and tolerably thick 
or less depressed than in the preceding Insects. Their posterior 
legs are densely ciliated, resemble oars, and are terminated by two 
very small and rather indistinct hooks. ‘They swim or row with 
great swiftness, and frequently while on their back. They compose 
the genus 
NoronectTa, Lin. 
Which has been divided in the following manner: 
- “« 
Corrxa, Geoff.— Sigara, Fab. 
Where the scutellum is wanting(1); the rostrum is very. short, 
triangular, and transversely striated; the elytra are horizontal; the 
anterior legs are very short, and their tarsi formed of a single com- 
pressed and.ciliated joint; the other legs are elongated, and the two 
intermediate ones are terminated by two very long hooks. 
« + C. striata; Notonecta striata, L.; Roes., Ib., XXIX. The 
largest specimens are about five lines in length; dark brown 
above, with numerous yellowish dots or little stripes; head, legs, 
» and all underneath, yellowish(2). 
Noronecta, Geoff. Fab.’ 
Where the scutellum is very distinct, the rostrum forms an arti- 
culated and elongated cone, the wings are tectiform, and all the tarsi 
biarticulated. The four posterior legs are geniculate, and have sim- 
ple, cylindrical tarsi, terminated by two hooks. 
NV. glauca, L., Res., Ib., XXVII. Six lines in length; yel- 
lowish above, with a russet tint on the elytra, the inner margin 
of which is spotted with blackish; scutellum black. 
To seize its prey with more facility it swims on its backs it 
stings severely(3). 
' (1) The Notonecta minutissima, Fab., is the type of the genus Sigara of Leach— 
Lin. Trans., XII. The anterior tarsi, as in Corixa, consist of one joint, but this 
Insectis furnished with ascutellum. Its thorax is transversal, and body oval, and 
not linear or cylindrical. 
(2) For the other species, see Fab., Syst. Ryng. 
(3) Fab., Syst. Ryngot.; Lat., Gener. Crust. et Insect., II, p. 150. The genus 
Plea, Leach, which that gentleman establishes on the Notonecta minutissima of 
Linnzus, and which must not be confounded with the one so styled by Fabricius 
and other entomologists, differs from Notonecta, inasmuch as the third joint of the 
