﻿82 [September, 



by the late Mr. Ashworth in North Wales was sent, amongst other 

 insects, for names, by Mr. Edleston ; and Dr. Power has proposed for 

 it the name of Asliworthi, in case of its proving an undescribed species. 

 There is, I think, no doubt it is the H. dbsoletus of Aube. Its occurrence 

 in this country is remarkable and unexpected ; for it is a native of 

 Syria, and Southern (more especially South-eastern,) Europe. The 

 geographical distribution in Europe, however, of several species of 

 Hydroporus is most eccentric. Thus, H. 5-lineatus has been found only 

 in Lapland and on the borders of England and Scotland, and H. 

 xantliopus, Steph., only in Southern Europe and Britain, and yet I have 

 taken these two species near Dumfries on the same day, and in the 

 same pond. 



H. NIGRITA. 



Under this name we have mixed in our collections two species, 

 the synonymy of which is very complicated. In my references 

 given below, I have omitted to quote the earlier authors, as the 

 descriptions of Fabricius, and even of Gyllenhal, are altogether un- 

 certain ; with respect to the latter author it is however necessary to 

 remark that, in the 9th vol. of Sk. Col., Thomson has reversed the 

 interpretations generally given to Gyllenhal's descriptions of H. pubes- 

 cens and nigrita, because Gyllenhal says that pubescens is shorter and 

 broader than nigrita. In direct opposition to this change is, however, 

 the colour given by Gyllenhal ; for he says of pubescens that the elytra 

 are testaceous, a term which might be correctly applied (at least to 

 some of its vars.) to the species generally called H. pubescens, Gyll., 

 but which is totally inapplicable to the species which Thomson now 

 proposes to so designate. Nevertheless, Thomson's remark is in itself 

 perfectly correct, and it must be understood that the assignment of the 

 description of H. pubescens, Gyll., to the insect we know by that name, 

 is conventional, and traditional, rather than evident from the descrip- 

 tion itself. 



The two species we have mixed as H. nigrita are — 



1. A black Hydroporus very like H. pubescens, Gyll., but shorter, darker in 

 colour, and with rather denser punctuation : this species is clothed above with a 

 distinct pubescence, the removal of which leaves the upper surface of the insect 

 shining. The synonymy appears to be, — if. discretus, Fair., Ann. Fr., 1859, p. 28 ; 

 Sch., Ins. Deutsch., i, 2nd pt., p. 64 ; H. nigrita, Sturm. Ins. Deutsch., ix. 56 ; 

 Th., Sk. Col., ii, 24 ; H. pubescens, Th., Sk. Col., ix, 79. 



2. A black Hydroporus in which the punctuation and pubescence is very much 

 more sparing than in the preceding species, and whose upper surface is dull, owing 



