NEW BRITISH SPECIES NOTICED IN 1859. 107 



Taken by Dr. Power at Shirley, near Croydon, and at 

 Merton, Surrey, and by Mr. Waterhouse, at Southend, 

 Essex. 



13. Stenus proditor, Eric. ; E. W. Janson, Proc. Ent. 



Soc. 4 April, 1859, Zool. 6613 (1859). 

 Stenus proditor, Eric. Kaef. d. Mark Brand, i. 550, 



24 (1839), Gen. et Spec. Staph. 713, 44 (1840); 



Heer, Faun. Col. Helv. i. 220, 22 (1839) ; Redtenb. 



Faun. Austr. Ed. i. 727 (1849), Ed. ii. 222 (1857); 



Fairm. et Laboulb. Faune Ent. Franc, i. 585, 40 



(1856); Kraatz, Naturgesch. d. Ins. Deutschl. ii. 



768, 33 (1857). 

 Very similar to S. Argus, but narrower, the head wider, 

 the tarsi more slender, and the abdomen conspicuously mar- 

 gined throughout, rather more thickly punctured, the base of 

 each segment with a short longitudinal ridge. 



I captured a single example, early in December, 1858, at 

 roots of grass in a swamp in a wood near Finchley, Mid- 

 dlesex. 



14. Stenus opticus, Grav. ; E. W. Janson, Proc. Ent. 



Soc. 4 July, 1859, Zool. 6656 (1859). 

 Stenus opticus, Grav. Mon. Col. Micr. 231, 12 (1806) ; 



Eric. Kaef. d. Mark Brand, i. 560, 36 (1839), Gen. 



et Spec. Staph. 720, 57 (1840) ; Heer, Faun. Col. 



Helv. i. 222, 31 (1839) ; Ptedtenb. Faun. Austr. 



Ed. i. 728 (1849), Ed. ii. 223 (1857); Fairm. et 



Laboulb. Faune Ent. Franc, i. 587, 48 (1856) ; 



Kraatz, Naturgesch. d. Ins. Deutchl. ii. 778, 47 



(1858). 

 Stenus femorellus, Zetterst. Ins. Lappon. 71, 13 (1840), 



sec. Eric. /. c. 

 Pertaining to Group I. (fourth joint of the tarsi simple), 



