CORIXINA. 49 



the third. Eyes remote, slightly prominent. Rostrum 3-jointed, 

 short, obtuse ; the first joint nearly covered by the labrum and cheek- 

 plates. Pronotum convex, transverse, obscurely hexagonal. Elytra 

 corneous ; Corium, the posterior margin of each elytron meeting each 

 other in a straight longitudinal line ; Embolium linear, placed ob- 

 liquely on the anterior angles ; Membrane wanting. Sternum visible 

 horizontally only as the edges of thin plates between the deeply 

 inserted coxa3, laterally as triangular plates. Legs all formed alike ; 

 coxce large ; fulcra, third pair angulated ; thighs gradually smaller to 

 the apex ; tarsi trimerous. Gren. 1, Plea. 



SECTION $. CORIXINA. 



Notonectici, p., Burm. 

 Notonectidae, p., Westw. 

 Corisides, Am. et Serv. 

 Corisoidae, Fieb. 

 Corisidea, Fieb., Flor. 

 Corisse, Fieb. 



Head scutellate, greatly curved under, so that the apex rests 

 between the anterior COXSB, the posterior margin overlying the pro- 

 notum. AntenncB simple, 3 or 4-jointed, inserted under the margins 

 of the head. Eyes large, remote. Rostrum short, unarticulated, 

 concealed ; labrum triangular, transversely wrinkled ; labium smooth, 

 covered by the labrum. JPronotum transverse triangular. Scutelluin 

 0, or short, triangular. Elytra pergamentous throughout ; Embo- 

 liuin long, linear ; Clavus broad, triangular ; Membrane indistinctly 

 separated from the corium ; nerveless except one fine, long inner 

 nerve. Wings ample, very delicate. Sternum with Scapulce, Pleurce, 

 and sometimes Parapleurce ; Prosternum anteriorly bilobed ; Meta- 

 sternum produced into a triangular xyphus. Legs : each pair of dif- 

 ferent form ; first pair inserted posteriorly on the prosternum, stout, 

 short ; the tarsi monomerous, broad, cultrate, differing in the sexes, 

 pectinated, with strong hairs beneath, and one small setaceous, 

 apical claw; second pair, the thighs longest, simple, tarsi 1 or 

 2-jointed, with two long claws ; third pair, tarsi long, dilated, 

 2-jointed, long-ciliated, and with one apical claw. 



4 



