722 On Aquatic Carnivorous Coleoptera or Dytiscidce. 



cases is more definitely limited in its area than in the preceding form, the sutural 

 portion being quite smooth except on the basal one-fourth or one-fifth, and there 

 is also a much larger apical portion free from sculpture ; the thoracic sculpture is 

 the same as in the Mauritian form, but that on the head is but slight, there being 

 only some scratches in the neighbourhood of the eyes. In this therefore the chief 

 difierence from, the Mauritian form is that the sculpture is more concentrated on 

 the middle portions of the body : it is possible that this is the insect Klug described 

 as Cybister vulneratus. 



The males of these forms can scarcely be distinguished inter se. The Madagascar 

 individuals are usually rather broader than the African ones, while the Mauritian 

 examples are rather broader and shorter, and the Arabian individuals are rather 

 narrower, and approach nearer to a truly elliptical form than do any of the others. 



The species varies a good deal in size and colour, independently of the local 

 variations, and the size of the patch of sexual hairs on the male middle tarsus like- 

 wise varies somewhat : as does also the supplementary obsolete claw of the female 

 hind tarsus ; I have indeed an individual of this sex from Lake Nyassa in which no 

 trace of this claw can be detected. 



The species is widely distributed in Africa; in the North it reaches to the coasts of the South of Europe, 

 but is there very rare, while in the South it extends to Lake Nyassa ; it is also found in IMadagascar, 

 Mauritius, and Ai-abia (Hedjaz, Dr. 0. Millingen). 1063. 



1134. Cybister insignis, n. sp. — Ovalis, anterius angustatus, nigricans, prothorace 

 ad latera vage ferrugineo, pedlbus anterioribus et intermediis, (antennisque ?) rufis ; 

 pedibus posterioribus piceis, tarsis fere nigris. 3Ias, Long. 26, lat. 13i- m.m. Fern., 

 Long. 26, lat. 12 m.m. 



The male of this species has the front tarsi large, attaining 3 m.m. in the trans- 

 verse direction ; the intermediate tarsi, have on the basal joint beneath, a very large 

 and broad patch of short sexual pubescence, and there is also a large patch on the follow- 

 ing joint, the claws are elongate and nearly straight, the anterior one being thick, 

 and but little longer than the other. The female has the occiput, the thorax and 

 the elytra covered with deep, coarse scratches ; the sculpture on the elytra consists 

 of deep coarse elongate scratches which extend about four-fifths of the length of 

 the elytra, but are represented near the suture by onlj' a few scratches, near the 

 lateral margin there is a land of plica or fold, and the sculpture is abruptly termi- 

 nated at this fold, so that within the lateral margin there appears to be, as it were, 

 a smooth groove, which commences in an indefinite manner a little behind the 

 shoulder, gets broader as it goes backwards, and extends as far backward.s as the 

 scratches do ; the epipleurse of the elytra are broad, flattened and obliquely perpen- 

 dicular a little distance behind the shoulder, and the supplementary claw of the 



