HEMIPTERA HETEROPTERA. 163 
Fam. 3. GERRIDA. 
Gerride, Serv. Hist. Hem. 418—Hydrobatida, Stal, Hem. Afr. iii. 168— 
Hydrometre, Fieb. Eur. Hem.—Hydrometride, Dougl. and Scott, 
Hem. 40. 
A. Fore tibia with a distinct apical tooth. 
a. Abdomen very short. - - - - 3. HatosaTEs. 
b. Abdomen almost as long as the thorax. - - 2, PritomeRa. 
B. Fore tibiz with no distinct apical tooth. - - 1. GeRRIs. 
Genus 1. GERRIS. 
Gerris, Latr. Gen. iii. 183. Schum. Beitr. 11. Serv. Hist. Hem. 414— 
Hydrometra, Fabr. Syst. Rhyn. 256. Burm. Ramb. Fieb. Eur. 
Hem. 106. Dougl. and Scott, Hem. 557—Tenagogonus, Stal, Ofv. 
K. V. Ak. Forh. x. 263; Hem. Afr. iii. 1683—Limnoporus, Stal, Ofv. 
K. V. Ak. Forh. xxvi. 398—Limnogonus, Stal, Ofv. K. V. Ak. Forh. 
vii. 132—Limnotrechus, Stal, Ofv. K. V. Ak. Forh. xxv. 398—Hygro- 
trechus, Stal, Ofv. K. V. Ak. Forh, xxv. 398. 
Europe. 
1, GERRIS RUFOSCUTELLATA. 
, Stoll, Pun. pl. 15, f. 108 —Gerris rufoscutellata, Lair. Gen. iii. 134. 
Schum. Plot. pl. 3, f.1, 2; pl. 4, f.1, 14—19 — Hydrometra lacustris, 
Fall. Hem, 159—Hydrometra rufoscutellata, H.-Sch. Wanz. Ins. ix. 
69, pl. 300, f. 924. #ieb. Hur. Hem. 106—Limnoporus rufoscutellatus, 
Stal. 
Europe. 
2. GERRIS PALUDUM. 
Gerris paludum, Fabr. Ent. Syst. iv. 188. Schum. Beitr. Plot. 29, pl. 4, 
f.5—13. Brull. Hist. Nat. Ins. ix. 302. Blanch. Hist. Nat. Ins. 
iii. 97, Serv. Hist. Hem. 417—Hydrometra paludum, Fabr. Syst. 
Rhyn, 258. Zett. Ins. Lapp. 281. H.-Sch. Wanz. Ins. ix. 67, pl. 300, 
f. 926. Burm. Handb. Ent. ii. 210. Fieb. Eur. Hem. 106, Flor, 
Rhyn. Liv. i. 732.  Dougl. and Scott, Hem. 559—Hygrotrechus 
paludum, Stal. 
a—n. England. 
o, p. South France. 
3. Gerris Nagus. 
Cimex Najus, Deg. Ins. iii. 311, pl. 16, f. 8, 9—Gerris aptera, Wimm. 
Schuml. Plot. 34, pl. 4, f.4, 20—24 — Gerris canalium, L. Duf. Rech. 
Hem. 69, pl. 5, f.59.  H.-Sch. Wanz. Ins. pl. 300, f. 925, K, L, M. 
Serv. Hist. Hem. 418—Hydrometra aptera, H.-Sch. Wanz. Ins. ix. 
69, pl. 300, f. 925—Hydrometra Najus, Fieb. Eur. Hem. 107. Dougl. 
and Scott, Hem. 560—Hygrotrechus Najus, Sc¢al. 
a, b, France. 
