On Aquatic Carnivorous Coleoptera or Di/tiscidce. 673 



1052. Dytiscus sulcatum, Lin., AcUius sulcatus, lif.C — Latus, supra parum con- 

 vexus, capite prothoraceque testaceis, signaturis transversis nigris, elytris fusco 

 testaceis, nigro-irroratis, subtus prosterno testaceo, pectore abdomineque nigris, 

 hoc lateribus marginibusque ftavo-signatis, pedibus anterioribus testaceis, poste- 

 rioribus basi, tibiis tarsisque nigricantibus ; corpore creberrime punctato : antennis 

 elongatis tenuissimis. Long. 16, lat. 10 m.m. 



Mas, parum nitidus, corpore superne creberrime punctato. 



Fem., protborace medio utrinque versus latei'a subimpresso ibidemque villoso, 

 elytris sulcis latis viilosis integris. 



In the male the three basal joints of the front tarsi are greatly dilated, the basal 

 joint is large, and bears beneath a single very large cupule, the other two joints are 

 very short ; the undersurface of the tarsus beai's besides the large cupule two 

 much smaller cupules, and externally two patches of dense hairs bearing very 

 minute palettes ; the fringing hairs are elongate and beautifully developed. The 

 middle tarsi are not incrassate, but still are a little thicker and have the two apical 

 joints more elongate than in the female ; the three basal joints have their inner 

 and lower edge armed with a tuft of long hairs, of which the basal one is most 

 highly developed ; their undersurface has close to the marginal setse a few hairs 

 bearing minute palettes. In the female the grooves on the elytra are elongate and 

 very broad, they commence very near indeed to the base, and are continued nearly 

 to the apex, the inner one is, however, shorter than the one next it, the termina- 

 tion of this furrow also is more gradual than that of the others, so that its length 

 at the apex is slightly variable. 



The black marks on the head of this species may be said to be three in number, 

 one in front of the other — viz., the vertex is black, and there is an angular black 

 mark in front of it, and at the sides connected with it, while the third and most 

 anterior mark is a triangular black patch, whose outer and front angles reach the 

 clypeal suture. The thoracic black mark consists of two lines across the middle, 

 more or less connected at their extremities. 



The species varies in the extent to which the black colour of the upper surface is 

 developed, and in Scotland a variety is found in which the upper surface is nearly 

 entirely black. 



Europe ; from Sweden and Finland to Spam, Russia. 956. 



1053. Dytiscus fasciatus, de Geer, Acilius fasciatus, M.C. — Sat latus, supra 

 parum convexus, testaceus, capite prothoraceque signaturis transversis nigris, elytris 

 fusco-testaceis, nigro-irroratis, subtus pectore nigricante, abdomine plus minusve 

 nigro-fasciato ; pedibus posterioribus rufescentibus ; corpore creberrime punctato ; 

 antennis elongatis tenuissimis. Long. 15i, lat. 9i m.m. 



Mas, parum nitidus, corpore superne crebenime punctato. 



