On Aquatic Carnivorous Coleoptera or Dytiscidce. 697 



sides of thr, thorax ; in certain individuals these corrugations become coarse and 

 deep, and in the most extreme cases are accompanied by a radial corrugation on 

 the disc of the thorax ; these extreme females were considered by Aube to be the 

 males of Dytiscus verrucifer, Sahl. 



Europe and Siberia; (Sweden; Finland to 67°, Salilberg ; Germany, Belgium, Northern France, 

 Piedmont). 996. 



1092. Dytiscus verrucifer, Sahl., Ins. fenn., p. 1.59. ^Sat convexus, nitidus, 

 testaceus, capite vertice signaturisque frontalibus prothoraceque fasciis duabus 

 nigris, elytris creberrime nigro-vermiculatis, prothoracis fascia nigra anteriore 

 marginem anteriorem hand attingente, fascia posteriore lateraliter ante angulum 

 posteriorem desinente ; elytrorum epipleuris angustis. Long. 1.5, lat. 8f m.m. 



In the male of this species the front tarsi bear about fifty-six smaller palettes, 

 besides the three larger ones ; the intermediate feet have thirty-six palettes arranged 

 in an irregular manner. 



The female has the whole of the upper surface of the prothorax traversed by 

 deep rugPB or corrucations, which have a somewhat radiate arrangement on the 

 disc : the elytra, too, are covered with very deep furrows, which cause the surface 

 to appear densely packed with flattened tubercles ; these tubercles are more or less 

 elongate or confluent in the longritudinal direction. 



This insect differs from Dytiscus zonatus by the greater number of palettes on 

 the front and middle feet, and by the peculiar sculpture of the female ; the under 

 surface and the posterior tarsi are sometimes a little infuscate or piceous ; and the 

 colour of the wing-cases appeal's more obscure, owing to the black vermiculations 

 being thicker so that the yellow specks are more reduced than in D. zonatus. 



Finland, Sweden, Lapland, and Siberia. 997. 



1093. Graphoderes piciventris, Thorns, (ex parte), Sk. Col. X, p. 351. — Sat 

 convexus, nitidus, testaceus corpore subtus ex par<:e infuscato, capite vertice 

 signaturisque frontalibus nigris; prothorace ex parte majore nigro, medio lateri- 

 busque testaceis ; elytris testaceis creberrime nigro-vermiculatis, punctis testaceis 

 obscuris ; epipleuris angustis. Long. 15J, lat. 9i m.m. 



In the male of this insect there are about 74-80 small palettes, besides the three 

 larger ones, on the undersurface of the front tarsi, the intermediate feet present a 

 broad sole bearing about 42-52 palettes. The female has the whole of the ujiper- 

 surface of the prothorax traversed by very deep rugae or corrugations, assuming 

 a radiate arrangement on the disc : the elytra bear coarse flattened tubercles which 

 are quite isolated from one another, and have no tendency to be confluent in the 

 longitudinal direction. 



