11 



Genus [90]. Hygrotus. Steph. Ten species. 



H. confluens, Fab. Testaceous; head slightly darker, with 

 the occiput black or dusky ; elytra with five black, longi- 

 tudinal, parallel lines, the first and third from the suture 

 abbreviated in front, and all confluent behind; if line; 

 common. PL 13. fig. 1. 



Genus [91]. Hydroporus. Clairv. Forty-four species. 



H. 12. pustulatus, Fab. Ochraceous, the thorax with a 

 basal bilobate, black mark ; elytra also black and each with 

 six pale spots, three sutural and three marginal ; three 

 lines ; ponds and ditches. PL 13, fig. c 2. 



Group II. COLYMBETINI. Erichson. 



Genus [9 2]. Noterus. Clairv. Two species. 



N. crassicornis, Fab. Ferruginous ; elytra darker, with 

 their margin pale ; 2 \ lines; ponds and ditches. PL 13, 



fig- 3. 



Genus [93]. Laccophiltjs. Leach. Two species. 



L. minutus, Lin. Testaceous-yellow; the elytra fuscous 

 with the margin and some irregular discoidal spots, paler ; 

 two lines ; ponds and ditches. PL 13, fig. 4. 

 Genus [94]. Agabus. Leach. Twenty-nine species. In the 

 type only are the antennas in the male serrated ; in the female 

 the antennae and feet are always simple. The genus is also di- 

 vided into sections and subsections from the acetabula of the 

 underside of the male anterior tarsi and the ciliation of their 

 posterior tarsi. 



A. serricornis, Payk. Pitchy ; the lateral margins of the 

 thorax and elytra rusty red ; six lines ; very rare, Shrop- 

 shire. PL 13, fig. 5. 

 Genus [95]. Ilybius. Erichs. Six species. 



I. ater, Fab. Black, subasneous, the external margins 

 reddish brown ; the elytra with two pale pellucid shots ; 

 six lines; common. PL 13, fig. 6. 



Genus [96]. Colymbetes. Clairv. Six species. Anterior 

 tarsi of male with three dilated joints. 



C. striatus, Lin. Fuscous; thorax ferruginous, black in the 

 centre ; margins of elytra testaceous and legs black ; eight 

 lines; ponds and ditches, common. PL 14, fig. 1. 



Group III. DYTISCINI. Erichson. 



Genus [97]. Dytiscus. Lin. Five species. In the female an- 

 terior tarsi simple, and elytra usually furrowed longitudinally. 



