352 On Aquatic Carnivorous Colenptcra or Dytiscidce. 



266. Hydroporus saucius, Desb. Mitt. Schweiz. ges. Ill, p. 33S. — Ovalis, nigri- 

 cans, thorace in .medio elytrisque maculis parvis externis testaceis, pedibus fuscis, 

 antennariim basi dilutiore ; elytrorum lateribus distincte curvatis ; coxis pos- 

 terioribus medio sparsim fere fortiter punctatis ; elytris dense subtiliter punctatis. 

 Loner, vix 2, lat. 1 m.m. 



Very closely allied to Bidessus coxalis and probably only a variety of it, but 

 rather larger and darker in colour, .so that the pale marks on the elytra have 

 nearly disappeared. 



Corsica. 12i. 



267. Hydroporus minutissimus. Germ., M.C. — Angustulus, suboblongus, tes- 

 taceus, subtus leviter infuscatus, prothorace basi medio elytrisque fasciis transversis 

 nigris, elytrorum lateribus sat curvatis ; coxis posterioribus medio crebre subtiliter 

 punctatis ; elytris dense subtilissime punctatis. Long. 1§, lat. 1 m.m. 



I have from Switzerland a pale variety which in some respects is intermediate 

 between this and Hydroporus delicatulus. 



In Corsica there occurs a dark variety with the black marks of the upper surface 

 much extended. 



Europe, from South of England to Algeria ; Corsica, and Canary Islands. 122. 



268. Hydroporus delicatulus, Schaum, Stet. Zeit., 1844, p. 198. — Elongatus, 

 anp-ustus, depressus, testaceus, elytris fasciis transversis fuscis ; elytrorum lateribus 

 vix curvatis ; coxis posterioribus medio crebre subtiliter punctatis ; elytris omnium 

 dense subtilissime punctatis. Long, if, lat. I m.m. 



Very closely allied to Hydroporus minutissimus but rather smaller, narrower, 

 and paler in colour, with the punctuation of the coxae and elytra a little finer ; the 

 basal fascia of the elytra indistinct : it is possible that in Switzerland specimens 

 may be found to connect these two forms. 



Schaum did not distinguish Bidessus coxalis from this and the preceding species, 

 and consequently considered Hydroporus minutissimus as an intermediate form of 

 Bidessus coxalis and Hydroporus delicatulus. 



Europe, (Germany). 123. 



Group 5. (A. Each wing-case with a sutural stria). 



269. Dytiscus geminus, Fab., Hydroporus geminus, M.C. — Niger, vix nitidus, 

 thorace in medio rufescente, elytris testaceis plaga magna irregulari nigra ; thorace 

 sparsim subtiliter punctate : elytris crebre subtiliter punctatis, et pubescentibus, 



