DtjtistUS.'] ADEPIIAGA. 205 



of thorax and elytra yellow, antenn;c red; legs pitchy black; prosternal 

 process elongate, rather acuminate ; coxal processes rounded; elytra witli 

 a longitudinal impression behind middle ; male shining, female dull, 

 more closely punctured, deeply sulcate from base to beyond middle. 

 Long. 27-29, lat. 13-14 mm. 



Ponds and slowly running streams ; widely distributed and not uncommon throngh- 

 out England and Wales ; Scotland, local and not common but widely distributed. 

 Ireland, near Belfast and Dublin. 



D. marg-inalis, L. ( g var. = conformi.-^, Kunze). Olive black above 

 witli the margins of elytra and the whole border of thorax yellow, tes- 

 taceous beneath with the metasternum dark in the middle, antennae and 

 legs red, posterior pair more or less pitchy ; prosternal process broad not 

 elongate, coxal processes short, rather acuminate ; male shining, female 

 dimorjihic either sulcate and dull, or as in male except that the elytra 

 are more closely punctured towards apex ; size variable. Long. 26-34, 

 lat. 16-18 mm. 



By far the commonest of our species ; found in ponds and pools throughout the 

 kingdom : it ranges across Northern Europe and Asia to Japan and North America. 



D. circuznflexus, F. ( ? var. = iwri^lexiu, Lac). Rather elongate ; 

 upper side olivaceous, sometimes greenish, with margins of elytra and the 

 whole border of thorax yellow ; scutellum yellowish ; under side testa- 

 ceous marked with black ; antennt\3 and legs red, posterior pair more or 

 less pitchy; prosternal process rather elongate; coxal processes verj^ long, 

 narrow, and sharp ; male shining, female dimorphic, sulcate and dull, or 

 as in male except that the elytra are more punctured towards apex. 

 Long. 28-35, lat. 16-17 mm. 



Not common; found chiefly in the London district; Lee; Peckham, Lewisham, 

 Norwood, Camberwcll, Battersea, Red Hill, Shcerness; formerly recorded from 

 Swansea and from Lawrence Waltham, Berks; it is chitfly a South European 

 species. 



D. circumcinctus, Ahr. ( $ var. = duhius, OylL). Upper side 

 blackish or olivaceous with the margins of elytra and the whole border 

 of thorax yellow or yellowish red, under side testaceous, with meta- 

 sternum dark in middle, antenuce and legs red, posterior tarsi pitchy ; 

 prosternal process broad, not elongate ; coxal processes narrow and acu- 

 minate, but not much prolonged ; male shining, female dimorphic, sid- 

 cate and dull, or as in male, but with the elytra more strongly punctured 

 towards apex : very like D. 7/iarginfiliK, but distinguished l)y the acute 

 coxal processes, and the narrow yellow border round eyes ; the punctua- 

 tion also on the thorax of the sidcato females isiiner; in Dr. Power's 

 collection there is a female that comes between the two forms, the sulci 

 being only rudimentary but distinctly traceable. Long. 32, lat. IG mm. 



Rare; Cambridge Fens (Whittlcsca Mere, Wickcu Fen, &c.) ; Deal; Eastbourne; 

 Askham Bog, York ; it is found in North America. 



D. lapponicns, (lyll. ( ? var. = f"2'f<nfrionali>:, (lyll ). Uppi-r sur- 



