On Aquatic Carnivorous Coleoptera or Di/tiscidce. 259 



I. I.— Genns PELOBIUS. 



Posterior coxse separated from the metasternum by a suture which extends 

 directly outwards, not at all forwards ; metasternum in the middle behind with a 

 piece marked off by a distinct suture ; swimming legs slender, but with long cilise, 

 their tarsi elongate and slender ; prosternal process, elongate, bluntly acuminate 

 at the tip. 



This genus comprises only three species, one of them European, the others 

 Australian ; the European species, has the scutellum quite exposed, but in those 

 from Australia this part is nearly covered by a prolongation of the base of the 

 prothorax. 



1. Dytiscus tardus, Herbst. Hyclrachna tarda, M.C.* — Convexus, sine 

 pubescentia fere opacus, ferrugineus, capite utrinque, prothoraceque anterius et 

 posterius nigricantibus, elytris fuscis, marginibus irregulariter late dilutioribus, 

 corpora subtus ex parte nigro, antennis pedibusque testaceis : prothorace basi et 

 apice elytrisque punctato-rugulosis ; corpore subtus dense subtilissime punctato. 

 Long. 10, lat. 6 m.m. 



The male has the three basal joints of the front and middle tarsi a good deal 

 dilated, and furnished on the under side with tomentum, the dilated joints are a 

 good deal compressed at the sides. 



Central and Southern Europe, Corsica and Algeria ; common in isolated spots. Not found in 

 Scotland, Denmark, Finland or Scandinavia. 235. f 



2. Pelobius australasise, Clark. Ilydrachna Australasice, M.C. — Convexus, 

 sine pubescentia, sat nitidus, niger, thorace, elytris, antennis pedibusque ferrugineis; 

 prothorace dense subtiliter, asqualiter punctato, elytris dense subtiliterque punctato- 

 rugulosis ; corpore subtus fortiter punctato. Long. 10, lat. 6 m.m. 



In the male the basal joints of the front and middle tarsi are slightly dilated 

 and are furnished beneath with tomentum, 



Australia, (Melbourne). 23G. 



The two Australians differ from D. tardus, by the small scutellum and obsolete frontal suture. 



*The name followed by the letters M.C. is that under which the species is recorded in the Munich 

 Catalogue of Coleoptera (Catalogus Coleopterorum, autoribus Dr. Gemminger et B. de Harold, Tom. II. 

 Monachii, 1868). Such specific names as are not recorded in the Munich Catalogue will be accompanied 

 by a reference to the actual work in which the original description appeared. Both these references are 

 a-bsent in the case of species here named and characterised for the first time. 



I The number placed in this position is that which I have used for labelling specimens and collections 



submitted to me for determination during the progress of the work. It may therefore be quite disregarded 



except by those who have from me specimens bearing these numbers. 



2 M 



TBANS. HOT. DUB. SOC, N.S. VOL. II. 



