On Aquatic Carnivorous Coleoptera or Dytiscide. 655 
1017. Hydaticus rectus, n. sp.—Minor, ovalis, nitidus, subtus piceus, prosterno 
testaceo, supra capite thoraceque rufo-testaceis, illo vertice, hoc basi et margine 
anteriore elytrisque nigris, his fascia transversa pone basin margineque laterali late 
et regulariter, testaceis ; antennis pedibusque quatuor anterioribus testaceis ; pedi- 
bus posterioribus rufis. Long. 102, lat. 5% m.m. 
The 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 ajex, it is however just a little dilated before the apex. It is smaller 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.—Regulariter 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 basal, 
linea humerali elongata, macula sublaterali pone medium alteraque subapicali 
testaceis, margine laterali intra epipleuram anguste vageque rufescente; antennis 
pedibusque anterioribus testaceis, tibiis intermediis picescentibus. Long. 13, lat. 
74 ™m.m. 
This species is closely allied te H. subfasciatus, but is larger and more elongate, 
the black colour on the wing 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 
ot H. subfasciatus, except that they are rather larger. 
South America, (Upper Amazons), 1028. 
1019. Hydaticus subfasciatus, Lap., M.C.—Ovalis, nitidissimus, niger, prosterno 
anterius testaceo, capite thoraceque rufis, illo vertice margineque interno oculorum, 
hoc basi in medio maculaque 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 62 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. 
