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, 



London, common. Fl. \4,Jiff. 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 h lines; ponds. 

 Fl. 14, fig. 3. 

 Genus [99]. Acilius. LeacJi. 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 



common; ponds. Fl. 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 tibise and tarsi pitchy ; one inch and 

 one line ; ponds, very rare. Fl. 14, fig. 5. 



Race II. GYRONECHINA. Kirb. and Sp. 



Family [9]. Gyrinid^:. Leach. 



Genus [101]. Gyrintjs. Lin. Eight species. 



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

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

 mon. Fl. 13, fig. 7. 

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

 the tarsi simple. 



0. villosus, Fab. Olivaceous, villose ; antennse ferrugi- 

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

 common. Fl. 13, fig. 8. 



Subdivision II. BRACHELYTRA. Latr. 

 Family [10]. OMALiDiE. Macleay. 

 Genus [103], Lesteva. Latr. Fourteen species. 



