424 On Aquatic Carnivorous Coleoptera or DytiscldcB, 



female, and the front ones have the claws longer and stouter ; the thorax is not 

 narrowed in front of the base so that its hind angles are free, the base being a 

 little wider than the shoulders of the elytra ; in the female the sides are a good 

 deal contracted just in front of the base so that the angles fall within the shoulders 

 of the elytra ; in the female there is a short indistinct plica near the outer edge 

 of the elytra at some distance before the apex, and the last ventral segment is a 

 little prominent on each side. 



Central Europe ; (widely distributed but rare ; from Scotland to Italy, and from Dalmatia to La 

 Vendue). 300. 



Group 2. 



462. Dytiscus duodecim-pustulatus, Fab., Hydroporus duodecim-pustidatus, 

 M.C. — Oblongo-ovalis, sine pubescentia, sub-opacus, testaceo-ferrugineus, thorace 

 anterius et posterius nigricante, elytris fusco-nigris, maculis fere quadratis testaceis 

 ornatis ; thorace lateribus valde rotundatis, angulis posterioribus obtusis ; corpora 

 subtilissime punctulato. Long. 5i, lat. 2f m.m. 



Mas, tarsis anterioribus et intermediis bene dilatatis, anterioribus unguiculis 

 majoribus, tibiis anterioribus et intermediis intus leviter curvatis, intermediis 

 angulo apicali interno unco parvo armatis. 



This species varies a good deal in colour, the elytra being sometimes nearly 

 entirely yellow while in other individuals tlie black colour occupies nearly all their 

 surface ; the underside also is more or less infuscate. 



Central and Southern Europe, (and Algeria ?) ; extends in the north to Scotland, and south of Swedeu, 

 wanting in Finland. 240. 



463. Hydroporus duodecim-maculatus, Eegt. Ann. Soc. Fr. 1877, p. cxxxiii. — 

 Oblongo-ovalis, sine pubescentia, testaceo-ferrugineus, capite intra oculcs, vertice, 

 thoraceque anterius et posterius nigro-marginatis, elytris nigris, maculis plus minusve 

 conspicuis testaceis ornatis ; thorace lateribus valde rotundatis, angulis poster- 

 ioribus fere rotundatis ; corpore subtus plus minusve infuscato. Long. 5|, lat, 

 vix 3 m.m. 



Mas, paulo longiore, tarsis anterioribus et intermediis bene dilatatis ; tibiis 

 intermediis intus curvatis, angulo apicali interno unco parvo armatis. 



Fern., opaca omnium dense subtilissime punctata. 



Although very closely allied to Dytiscus duodecim-pustulatus the sj^ecimens 

 before me of this species differ not only by their more rounded hind angles of the 

 thorax, but also by the sexual characters, the male front claws being shoi'ter, and 

 the anterior tibiae not curved inwardly, while the female differs more in appearance 

 from the male owing to the punctuation of the surface being more obsolete. The 

 colour no doubt varies a good deal. 



