HEMIPTERA. 167 



Ploiaria, Scop. — Emesa. Fab. 



Analogous to the preceding Insects in the linear form of the body, 

 and the length and tenuity of the legs; but the two anterior ones 

 have elongated coxae, and are adapted, as in Mantis, for seizing their 

 prey *. 



We now come to Geocorisse, remarkable for their large eyes, and 

 which have no apparent neck, but whose transversal head is sepa- 

 rated from the thorax by a strangulation. 



Tiiey live on the shores of ponds, &c. where they run with great 

 swiftness, and frequently make little leaps. 



Some have a short and arcuated rostrum, and setaceous antennae. 

 They form the 



Leptopus, Lat. t- 



In the others tlie rostrum is long and straight, the labrum projects 

 from its sheath, and the antennse are filiform or a little larger near 

 the extremity. The simple eyes are situated on a tubercle. They 

 are considered by Fabiicius as Saldae. 



Latreille separates them into tAvo divisions. His Acanthi^ — or 

 part of the Sald;e, Fab. + — have salient antennae, at least equal in 

 length to half that of the body. Their form is oval. The simple 

 eyes are closely approximated and sessile. In his Pelogonus § the 

 antennae are much shorter and bent under the eyes. The body is 

 shorter and more rounded, and there is a tolerably large scutellum. 

 The simple eyes are remote. These Hemiptera approach the Nau- 

 cores, and with the following appear to lead to them. 



Sometimes the four posterior legs, very slender and extremely 

 long, are inserted on the sides of the pectus, and are very remote 

 from each other at base ; the tarsial hooks are very small, but little 

 distinct, and situated in a fissure of the lateral extremity of the tar- 

 sus ||. These legs are adapted for swimming or walking on water, 

 and are peculiar to the genus 



Hydrometra, Fab. ^, 



Which Latreille divides into three subgenera : 



Hydrometra, Lat., 



Or Hydrometra properly so called, Avhere the antennae are setace- 

 ous, and the head is prolonged into a long snout, receiving the rostrum 

 in a groove underneath **. 



* Fab., Syst. Ryng. ; Gents vagabundus, Ejusd.; Lat., lb. 



t Lat., Consid. snr I'Oid. Nat. des Crust, et des Insect., p. 259. 



X Fab., lb. The Sf-lda; zostera, striata, littoralis : Lat., lb. 



§ Lat., Consid. sur I'Ord. Nat. des Crust et des Insect., Ill, p. 142 ; Germ. 

 Faun. Insect. Europ., XI, 23, 



II The prothorax is extended above the mesothorax, in the form of an elongated 

 plate, narrowed and terminated in a point, representing the scutellum, under which 

 the elytra originate. The mesothorax is greatly elongated. 



^ Frtb., Syst. Ryngot. 

 ^ ** Lat., Gener. Crust, et Insect. Ill, p. 131, 



