224 M0D£IIN SVSTEM. 



Fam. IV. Hydrometidx. Leuch. 



CiMlciDES I. 2. Lalrdlk. 



Rostrtaii with two or three distinct joints: lubrum verj' short: cijei 

 moderate : feet very long, formed for walking on the water, with the 

 nails very minute, inserted laterally into a tissure at the extremity 

 of the last joint of the tarsi. 



Genus 282. IIYDROMETRA. Latr., Lam., Fair., Leach. Cimex. 

 Linn., Geoff. Aquarius. SchcUenberg. 

 Anlennce setaceous, the third joint longer than the rest : anterior feet 



simple : licad clongate-cylindric, apex thickened. 

 Sp. 1. Hi/d. stagnorum. Black above: feet brown reddish. 

 Ilydrometra stagnorum. Fabr., Leach. Cimex stagnorum. Linn. 



Aquarius paludum. Schellenbcrg. 

 Inhabits Europe in most places, and walks on the surface of the water. 



Genus 283. VELIA. Latr., I^cach. Cimex. Rossi. Hydrome- 

 TRA. Fabr. 



Aalotnue {^Vii'orm, the first joint longest: anterior Jeet ra^itOYious : ros- 

 ^/M/rt two-jointed : head somewhat vertical. 



Sp. 1. Vel.rividorum. Black; sides of the thorax and margins of th« 

 abdomen red: thorax with two anterior punctures; each elytron 

 with three and a spot of white; inferior sides ot the abdomen punc- 

 tured with black. 



Hydrometra rivulorum. Fabr. Velia rivulorum. Latr., Leach. 



Inhabits running waters and springs. 



Genus 284. GERRIS. Latr., Leach. Cimex. Linn., Be Gcer, 

 Schrank, Geoff. 



Antenna filiform, the first joint longest, the last cylindric : anterior feci 

 raptorious : roAtrum three-jointed : head porrectcd. 



Sp. 1. Ger. paludiun. Brown-olive, black above, cinereous, silky be- 

 neath: abdomen nearly equally broad: trunk as long as the head, 

 carinated beneath, a series of impressed lines on each side : antenna 

 and feet black : thorax with an elevated line extending to the middle 

 of the back : lateral margins of the thorax and abdomen with the 

 anus reddish. 



Hydrometra paludum. Fabr. Gerris paludum. Latr., Leach. 



Inhabits ponds and ditches in Trance, England, and Sweden. 



0ns. — The species of this genus are certainly but little known; they 

 are either subject to great variation, or are very numerous. 



Fam. V, AcANTHiD^. Leach. 

 CiMiciDfis II. Lat7-eille. 



Luhrum \-ery prominent : eyes very large : feet formed for walking andl 

 jumping. 



