INSECTA. 443 



Gerris LATR., FABR. previously, Hydrometra FABR., BURM. (in 

 jjart). Four posterior feet very long, remote from anterior. First 

 oint of antennaa very long. 



Sp. Gerris lacustris, Cimex lacustris L., STOLL, Wantzen, Tab. ix. fig. 63; 

 DUMERIL, Cons. gen. s. 1. Ins. PL 36, fig. 6. This species often continues 

 wingless ; comp. Gerris canalium, LEON DUFOUR, Anat. des Hemipt. PL V. 

 fig. 59; Gerris rufoscutellata LATB., STOLL, 1.1. Tab. 15, fig. 108; Cuv. JR. 

 Ani. ed. ill., Im. PL 92, fig. 5, &c. 



Halobates ESCHSCH. 



Note. Species small, apterous, or with little elytra, with abdomen short, 

 conical, in tropical seas and the Pacific ; comp. EscHSCHOLTZ, Entomogra- 

 phien, i e Lieferung, Berlin, 1822, 8vo. pp. 106 in, Tab. III. figs. 3 5. 

 Are they larvae (and pupae) of species of genus Gerris ? Comp. the figure, 

 much resembling a larva recently excluded from the egg, of LEON DuFOUR, 

 Anat. d. Hemipt. PL xv. f. 178. 



Velia LATR. Feet sub-equally distant, the middle rather longer 

 han the rest. 



Velia WEST., BURM. First joint of antennae longer than rest. 

 Posterior femora incrassate, spinose. 



Sp. Velia rivulorum LATR., Gerris rivulorum FABR., Ent. Syst., Hydro- 

 metra rivulorum FABR., Syst. Rhyng., Cuv. R. Ani. ed. ill., Ins. PL 92, 

 fig. 4, &c. 



Hydroessa BURM., Microvelia WESTW. Last joint of antennae 

 longer than rest. 



Sp. Velia pygmcea, LEON DUFOUR, &c. 

 B. Claws of tarsi apical. 

 Hebrus WESTW., BURM. 



Hydrometra LATR. (species of Hydrometra FABR.), Limnobates 

 3uRM. Body narrow, elongate ; head protracted beyond the eyes. 

 Antennae with third and fourth joints elongate, third very long. 

 Feet very slender, long. 



Sp. Hydrometra stagnorum, Cimex stagnorum L., SCHELLENB. Cimic. Tab. ix. 

 fig. 2; DUMER. Cons. gen. s. 1. Ins. PL 37, fig. 5. This small needle-shaped 

 insect has much resemblance to the genus Ploiaria. 



Phalanx III. Nudicollia (Reduviidce WEST.). Sheath of ros- 

 trum triarticulate. Rostrum incurved. Head abruptly attenuated 

 towards the base, forming a distinct neck. Antennas with four 

 joints, sometime annulate or divided into secondary joints. Feet 

 long, with tarsi short, triarticulate, with two terminal claws. 



