On Aquatic Carnivorous Coleoptera or DytiscidcB. 655 



1017. Hydaticus rectus, n. sp. — Minor, ovalis, nitidus, subtus piceus, prosterno 

 testaceo, supra capite thoraceque rufb-testaceis, illo vertice, hoc basi et iiiargiue 

 anteriore elytrisque nigris, his fascia transversa pone basin margineque laterali late 

 et reguiariter, testaceis ; antennis pedibusque quatuor anterioribus testaceis ; pedi- 

 bus posterionbus rufis. Long. lOi, lat. 5f in.m. 



Tlie male tarsi are rather small, and their palettes are by no means large, and 

 the fringing hairs are not very highly developed. 



I have seen only a single male of this little species ; the broad lateral yellow 

 band of the wing-cases is very distinct and of nearly one width from the shoulder 

 to the apex, it is however just a little dilated before the apex. It is ^mailer than 

 the North American Dytiscus bimarginatus, and easily distinguished therefrom by 

 the conspicuous yellow transverse fascia near the base of the wing cases, and 

 the bright yellow red prothorax, with transverse black marks at the front and 

 base. 



South America, (Parana). 1029. 



1018. Hydaticus amazonicus, n. sp. — Reguiariter ovalis, fere elongatus, nitidis- 

 simus, niger, prosterno anterius rufescente, capite thoraceque rufis, illo vertice et 

 plaga inter oculos, hoc late in medio nigricantibus, elytris fascia transversa basali, 

 linea humerali elongata, macula sublaterali pone medium alteraque subapicali 

 testaceis, margin e laterali intra epipleuram anguste vageque rufescente; antennis 

 pedibusque anterioribus testaceis, tibiis intermediis j^icescentibus. Long. 13, lat. 

 7i mm. 



This species is closely allied to H. subfasciatus, but is larger and mure elongate, 

 the black colour on the Aving cases extends nearly to the apex, and the diminished 

 extent of yellow colour appears but little dotted with black. 



I have seen only one individual ; it is a male and has the tarsi similar to those 

 of H. subfasciatus, except that they are rather larger. 



South America, ( Upper Amazons). 1028. 



1019. Hydaticus sulifasciatus. Lap., .M.C. — Ovalis, nitidissimus, niger, prosterno 

 anterius testaceo, capite thoraceque rufis, illo vertice margineque interno oculorum, 

 hoc basi in medio niaculaque ad marginem anteriorem nigris, elytris ex parte 

 majore nigris, signatura humerali, fascia transversa pone basin, margine angusto 

 antice abbreviato, macula irregulari ad latera paulo ultra medium apiceque late 

 et confuse testaceis ; antennis pedibusque quatuor anterioribus testaceis. Long. 

 11, lat 6t m.m. 



The male front tarsi are not very large, but their fringing hairs and palettes are 

 well developed : the female has a somewhat circular patch of fine dense sculpture 

 on the thorax at some distance from each side. 



