On Aquatic Carnivorous Coleoptera or Dytiscidcr. 509 



The three basal joints of the front and middle tarsi are very little incrassate, and 

 are furnished beneath with short hairs, bearing very small and indistinct palettes, 

 the claws of the front feet are not elongate, and the anterior one has near the base 

 a sharp prominent tooth : the ditFerence in sculpture of the two sexes is extremely 

 sliglit. The pale marks on the elytra are sometimes not easily detected. 



Northern Europe, and Siberia ; (Sweden ; Finland to 08°, according to Sahlberg ; Britain, Northern 

 France ; Germany). 754. 



699. Agabus stridulator, n. sp. — Oblongo-ovalis, nitidus, niger, vix supra sub- 

 senescens, antennis pedibusque rufis, femoribus picescentibus ; supra Isevigatus, nullo 

 modo reticulatus. Long. 6, lat. 3i m.m. 



The basal joints of the front tarsi in the male are almost without incrassation, 

 and their clothing beneath is but little developed : the front claws are short, and 

 the anterior one bears beneath a sharp prominent tooth. There seems to be no 

 sexual difference in the sculpture of the upper surface ; but on the undersurface 

 the file on each side of the third ventral segment of the male is very distinct. 



The species is extremely closely allied to Dytiscus affinis, but is rather less 

 elongate, and its surface is destitute of the very rudimentary reticulation which 

 on careful examination may be detected in that species : the anterior tarsi of the 

 male have the basal joints less incrassate, the prosternal process is narrower; and 

 the hind coxsa are just slightly smaller, so that the wings of the metasternum are 

 just appreciably less reduced. As in D. affinis a pale dash may sometimes be seen 

 near the side of each elytron about the middle, and another near the apex. 



North America, (Hudson's Bay, Canada). 1156. 



700. Agabus {Eriglenus) unguicularis, Th. Sk. Col. IX, p. 101. — Ovalis, sat 

 convexus, niger, vix supra subsenescens, antennis pedibusque ruiis, femoribus 

 picescentibus subtilissime reticulatus, nitidus, elytris guttula pone medium 

 maculaque apicali pallidis ; elytris punctis subseriatis et apicalibus haud profundis, 

 epipleuris basi rufescentibus. Long. 6i, lat. 3i m.m. 



There is no difference in the sculjiture of the sexes in this species : the male has 

 the basal joints of the front and middle tarsi a little incrassate, and furnished 

 beneath with short hairs bearing very small palettes ; the claws of the front feet 

 are short, and the anterior bears a very sharp tooth in the middle beneath. 



Europe, (Sweden, South Finland, Stettin, Berlin, Britain). 757. 



s u > 



