224 [March, 



A single male in Dr. Power's collection taken on Moss Morran, 

 near Balmuto, Fifeshire, August 21st, 1872. 



This species is like G. Jacustris in form and size, but differs in 

 tlio colour of its autennte, its rufous prouotum, with the yellow streak 

 on the uudercurved sides distinct only posteriorly, its anterior legs 

 more black, the 1st joint of the posterior tarsi shorter, the form of 

 the genitalia, &c. 



Note. — The name of the genus Hydrometra, founded by Latreille 

 on Gimex stagnorum, Lin., was misappropriated by Fabricius to his 

 genus Gerris, with the species of which (except stagnorum) it had 

 nothing to do, the structure being essentially different. Most authors 

 have adopted this error ; Burmeister, seeing the incongruity, re- 

 separated stagnorum, but instead of restoring Latreille's generic name, 

 he coined a new one — Limnohates (cf. Pascoe, Ann. and Mag. Nat. 

 Hist., l^eb., 1SG8, and Dallas, Zool. Eecord, v, 353, 1869). 



COEIXINA. 



COEIXA PBOMIIfULA. 



Corisa prominula, Thoms., Opusc. Ent., i, 38, 20 (1869). 



Above fuscous-black ■with obscure yellow markings. Head obscure-testaceous, 

 in front evidently produced, posteriorly a short, projecting keel, 'with a row of 

 punctures on each side of it ; facial depression very slight and flat, extending beyond 

 the angles of the eyes. Pronotum short, with six pale lines. Elytra : clavus with 

 fine, pale, straight lines, at the base oblique but not widened, the rest often abbreviated 

 inwardly; corium with irregular pale lines, often confluent externally, traversed 

 by two longitudinal black lines, one close to the anterior margin and one near tho 

 clavus broad posteriorly : marginal channel obscure testaceous, on the basal half 

 darker and very narrow : membrane-suture pale ; membrane broadly black on the 

 margins and in the middle, otherwise with irregular pale markings. Sternum pale. 

 Legs dusky-testaceous, posterior tarsi clearer, with black cilia: $, tibia, 1st pair, 

 short, tumid ; palcB broadly cultrate, rounded externally and prolonged to a point. 

 5 , tibicE, 1st pair not tumid; palcB narrow-cultrate. Abdomen pale beneath, base 

 black in ^ . Length, 2^ lines. 



Like G. fossarum, but differs in being rather smaller, narrower, 

 Bides more parallel, head more prominent in front, marking more 

 obscure, &c. Also resembles G. Scotti, but differs in being distinctly 

 lai'ger, the pala) of the ^ much broader, &c. 



This species, found by Mr. II. Jenner-Fust, in the Isle of 

 Harris, Hebrides, in 1872, I at first sight took to be G.fossarum, but 

 afterwards, finding it differed, I kept it separate. It has lately been 

 identified by Dr. J. Sahlberg as G. prominula, Thoms., and, as it agrees 

 with the description, I bring it forward as a new British species. 

 Lee : December 27th, 1875. ^ 



