102 IIYDKADKPIIAGA — DYTISCIDAE. 



I, Base of thorax with an impressed longitudinal 

 line on each side, which is continued on the base of 

 elytra. 



1, Body bare; antennae entirely yellow. 



Head brownish-yellow, vertex darker; thorax yellow, 

 darker in front and behind ; elytra yellowish, with suture, 

 base, and tAvo waved transverse bands (attached to suture) 

 black, beside the suture runs a deeply engraved stria, 

 effaced behind; tlie impressed lines on the Itase of thorax 

 continued nearly to middle of elytra. L. | 1. Eare. 



H. iiiinutissimus, Germ. 



^, Body very finely pubescent ; antennae dark at 

 apex. 



A A. Sutural stria entire. 



Head brown : thorax reddish-yellow, anterior and pos- 

 terior margins more or less broadly brown-black, the im- 

 pressed lines on the base short and somewhat oblique ; 

 elytra black, wdth a toothed transverse band at base, and 

 the waved outer margin yellow. L. 1 1. Connnon. 



H. geminns, Fab. 

 JB li. Sutural stria al)l)reviated. 



Head pitch-brown ; thorax yellow, darker in front and 

 behind ; elytra pitch-brown, with some rust-reddish spots 

 on outer margin. L. f 1. Eare. H. unistriatus, Schr. 



II, Thorax with an impressed longitudinal line on 

 each side, parallel to side margin. 



Species pointed behind, more or less convex, slightly or 

 not at all hairy. 



1. Elytra black, witli a spot at base, connected 

 with another near apex by the outer margin and 

 a longitudinal line on the disc, yellow (thus en- 

 closing an oval black spot). 



Head reddisli, thorax brown, under-side red-lirown. 

 L. 1 1. Common. H. pict^ts, Fab. 



2. Elytra Ijlack, w^ith outer margin and two longi- 

 tudinal bands pale brownish-yellow. 



Head and thorax l)r(nviiisli-l)lack, latter somewhat red- 

 dish at margins ; under-side black, legs rust-red. L. 1 1. 

 Common. //. grannlaris, Lin. 



