aquatic Coleoptera from Ceylon. 347 



About twenty specimens, obtained most of them at 

 Bogawantalawa in March, represent three well-marked 

 varieties or races previously unknown to me. The diffi- 

 culties connected with the specific discrimination of 

 H. hihamatus and its allies have already been noticed by 

 myself, and more recently by Dr. Regimbart (Ann. Soc. 

 Ent. Fr., 1889, p. 154). If all the forms mentioned by 

 this savant be really one species the variation is extreme ; 

 but I think myself it is more probable that there will 

 prove to be several good species, each variable in colour. 

 At present sufficient materials for deciding this question 

 do not exist in our collections. H. fractifer, Walker, 

 is a variety not obtained by Mr. Lewis ; H. discindens, 

 Walker, is one of the varieties mentioned above. 



Hydaticus vittatus. 



Dytiscus vittatus, Fab., Syst. Ent., App., p. 825. 



Hadley. The specimens are of small size and narrow 

 form, with a greater development than usual of the 

 yellow colour on the thorax and elytra. Two specimens 

 from Lynford are a remarkable new variety, in which 

 the yellow colour occupies about one-half of the area of 

 the wing-cases. 



Sandracottus festivus. 



Dytiscus festivus, 111. Mag., i., p. 166. 



Bogawantalawa, in March. Two specimens. 



Cyhister ventralis. 



Cyhister ventralis, Sharp, Dyt., No. 1161, p. 742. 



This species is only known by one example of the 

 male sex from Madras. I refer to it with considerable 

 doubt three specimens from Ceylon in the collection of 

 Mr. Lewis, the form being more elongate than in the 

 typical example. These specimens were obtained from 

 different sources, and there is a great sexual disparity 

 between them ; but as there is not, under the circum- 

 stances, sufficient evidence that they belong to the same 

 species, I shall not remark farther on them. 



2a2 



