12 



D. circumflexus, Fab. Olivaceous ; margins of thorax, 

 lateral margins of elytra, and legs externally, testaceous ; 

 posterior tarsi black ; one inch and four lines ; ponds, Lon- 

 don, common. PL 14, fig. 2. 

 Genus [98]. Hydaticus. Leach. Four species. Tarsi in the 

 female simple. 



H. transversalis, Fab. Pitchy black; with the face in front, 

 thorax, excepting a patch at the base, lateral margins, and 

 an abbreviated, transverse, sinuated line at the base of the 

 suture all ferruginous ; legs pitchy red ; 2^- lines ; ponds. 

 PI. 14, fig. 3. 

 Genus [99]. Acilius. Leach. Two species. In female an- 

 terior tarsi simple, and elytra longitudinally furrowed. 



A. sulcatus, Lin. Fuscous ; the mouth and the margins, 

 and central transverse fascia of the thorax yellowish ; legs 

 testaceous ; their tarsi ferruginous ; 6 — 9 lines; very com- 

 mon ; ponds. PI. 14, fig. 4. 

 Genus [ 100]. Cybister. Curt. One species. Tarsi in female 

 simple. 



C. Roeselii, Fab. Olive black, face in front, and lateral 

 margins of thorax and elytra; dirty testaceous; legs tes- 

 taceous ; posterior tibiae and tarsi pitchy ; one inch and one 

 line ; ponds, very rare. PI. 14, fig. 5. 



Race II. GYRONECHINA. Kirb. and Sp. 



Fam. [9]. Gyrinid^e. Leach. 



Genus [10 1]. Gyrinus. Lin. Eight species. 



G. natator, Lin. Glossy blue black ; mouth rufescent ; legs 

 pale ferruginous ; three lines ; ponds and ditches, com- 

 mon. PI. 1.3, fig. 7. 

 Genus [102]. Orectochilus. Esch. One species. In female 

 the tarsi simple. 



O. villosus, Fab. Olivaceous, villose ; antennae ferrugi- 

 nous ; legs testaceous ; three lines, running streams, un- 

 common. PI. 13, fig. 8. 



Subdivision II. BRACHELYTRA. Latr. 

 Fain. [10], Omalidje. Macleay. 

 • [103]. Leiteva. Latr. Fourteen species. 



