of the Genus Hydroporus. 471 



colour of the thorax is flavous, with a tendency to rufo-flavous, the 

 Basal lhie and also two suhtriangular markings, one on either side of 

 the middle (which are connected with the base, but terminate at some 

 distance from the anterior margin) being fuscous : elytra broader, and 

 more rounded at the sides, than in H. assimilis, Payk. Six fuscous 

 lines, longitudinal, evenly disposed, and regular in continuation and 

 colour, extend from the apex to the base ; these lines are much narrower, 

 and the interstices broader, than in II. assimilis ; the testaceous colour 

 of the interstices between the 1st and 2nd lines (from the suture) is 

 interrupted at three points by a narrow fuscous junction of the lines 

 (basal, ante-medial, and post-medial), between the 2nd and 3rd at one 

 point (medial), between the 3rd and 4th at two points (medial, less 

 distinctly, and basal), between the 4th and 5th at no point ; the 5th 

 and 6th Hues take the usual form of broader abbreviated markings (in 

 H. assimilis the interstices between the lines are less interrupted) : 

 legs rufo-flavous, the anterior and the joints of the posterior tarsi being 

 fuscous : antenna flavous, the apical joints being fuscous. 



H. halensis is a trifle longer than H. assimilis, Payk. ; the apical 

 spines of the elytra are obsolete ; it is not so acute at the apex, and 

 (as will have been seen) differs widely in stronger pubescence and 

 coloration. The species is also closely allied to, but distinct from, H. 

 AndalusicB, described in this paper ; it is shorter and rounder in 

 form ; and the markings of the elytra are, in all the examples before 

 me, constant in their difference of pattern. It is perhaps most nearly 

 related to H. fuscitarsis of Aube, from Sardinia ; this latter species, 

 however, is impubescent, the general colour of the elytra is decidedly 

 darker by reason of the greater breadth of the fuscous lines, the general 

 form is narrower, and a trifle more parallel, than in H. halensis. 



Dr. Schauni has pointed out to me that our Scotch species, found 

 only in Mull (' Zoologist,' p. 4859), which has, since his paper in 

 the ' Zoologist ' (p. 1890), stood in our cabinets under the name of 

 halensis, Fab., is the true griseostriatus of DeGeer, — the error having 

 arisen from a confusion on the part of the late Mr. Stephens, between 

 his cabinet and his 'Manual' and < Illustrations,' and that this species 

 is the true halensis of Fabricius. 



This species has been twice taken in England — in Horning Fen, 

 Norfolk, by myself, in May 1855, in a running stream, and also, 

 by Dr. Ernest Adams, in a little river (" the Gipping ? ") near 

 Haughley, Stowmarket, Suffolk. 



H. derelictus, n. sp. 



H. ovalis, subparallelus, crebre punctatus (aliquando pene punctulatus), 

 pubescens, nitidus ( $ interdum opacus), ater : capite rufo ad apicem, ad 



