58 COLEOPTERA. 



4. Hydroporus brevis, Sahib., Nov. Col. Fenn. Spec. p. 



3 ; Thorns., Skand. Col. ii, 26, 28 ; G. R. Crotch, 



Cat. Brit. Col. ed. 2. 



According to Thomson this species is almost as large, but 



not so oval, as H. nigrita, Fab., having the sides of the thorax 



more delicately margined, and the disc smoother, the elytra 



almost glabrous, and the head pitchy. 



5. Hydroporus neglectus, Schaura, Stett. Ent. Zeit. 



1845, p. 409; J. A. Power, Ent. 26, p. 43. 



Taken by Dr. Power in a pit near Burnt-Ash Lane, Lee, 

 where it has also been found by Messrs. Douglas and Scott. 



It is one of our smallest unspotted species, and allied to 

 JS. tristis and S. uuibrosus, from the former whereof it may 

 be distinguished by its much smaller size, its more depressed 

 and less parallel form, and the greater curvature of the sides 

 of its thorax ; and from the latter by its smaller size, more 

 elongate and parallel form, entirely ferruginous legs and head, 

 and less pubescent, more finely punctured elytia. 



6. Gyrinus colymbus, Er., Col. March. 191, 2; G. R. 



Crotch, Proc. Ent. Soc. 19 Nov. 1866. 

 Mr. Crotch records a few specimens of this insect, found 

 among G.marinus (females) in his collection; and states 

 that the red reflexed margin at once distinguishes it. 



7. Gyrinus opacus. Sahib., Ins. Fenn. 4, 47, 3; G. R. 



Crotch, loc. cit. 



Mr. Crotch states that M. Scriba records this species as 



English in his paper (Stett. Ent. Zeit.); and adds that it 



appears to be not uncommon, and to be most nearly allied to 



G. marinus. Gyllenhal, indeed, seems to doubt whether it 



