224 
MOBERN SYSTEM. 
Fam. IV. Hydrometid.e. Leach. 
Cimicides I. 2. Lalrcille. 
Rostrum with two or three distinct joints: lubrum very short: eyes 
moderate : feet very long, formed for walking on the water, with the 
nails very minute, inserted laterally into a fissure at the extremity 
of the last joint of the tarsi. 
Genus 282. II Y DROMETRA . Latr., Lam., Fair., Leach. Cimex. 
Linn., Geoff. Aquarius. Schellenberg. 
Antenna setaceous, the third joint longer than the rest : anterior feet 
simple : head, elonghte-cylindric, apex thickened. 
Sp. 1. Hyd. stagnorum. Clack above: feet brown reddish. 
Ilydrometra stagnorum. Fabr., Leach. Cimex stagnorum. Linn • 
Aquarius paludum. Schellenberg. 
Inhabits Europe in most places, and walks on the surface of the water. 
Genus 283. VELIA. Latr., Leach. Cimex. Rossi. Hydrojie- 
tra. Fabr. 
Antenna fill Conn, the first joint longest: anterior feet raptorious : ros- 
trum two-jointed : head somewhat vertical. 
Sp. 1. Vel. rivulorum. Black; sides of the thorax and margins of the 
abdomen red: thorax with two anterior punctures; each elytron 
with three and a spot of white; inferior sides of the abdomen punc- 
tured with black. 
Ilydrometra rivulorum. Fabr. Velia rivulorum. Latr., Leach. 
Inhabits running waters and springs. 
Genus 284. GEltUIS. Latr., Leach. Cimex. Linn., De Geer, 
Schrank, Geoff. 
Antenna filiform, the first joint longest, the last cylindric: anterior fed 
raptorious: rostrum three-jointed: head porrectcd. 
3p. 1. Ocr. paludum. 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: antennas 
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. 
Ilydrometra paludum. Fabr. Gerris paludum. Latr., Leach. 
Inhabits ponds and ditches in France, England, and Sweden. 
Ons. — The species of this genus are certainly but little known; thi'jf 
are either subject to great variation, or are very numerous. 
Fam. V. Acaxtiud.e. Leach . 
Cimicides II. Latreillc. 
Labrum very prominent: eyes very large : feet formed for walking afld 
jumping. 
