1895. 169 



trifld, black at the apex ; its lateral lobes hook-like and curved upwardly, Hiu median 

 lobe thickened and rounded at the apex. The pair of hocks above the ventral plate 

 is strong and black. The base of the penis cover forms four little tubercles (the two 

 median being smaller), each of which bears a pellucid, acute and straight spine. In 

 all my examples, which are very numerous, the penis is retracted, but so far as one 

 can see, it is quite symmetrical, with a single sheath. 



? as usual in this genus. Expanse, <? , 5 mm. ; ? a little larger. 



This species is very distinct, ou account of the anal parts ot" the 

 (J. In its trifid ventral plate it shows aflBnity to O.faJcatfi, M.ovt., 

 but the form of the plate is very different. The lateral teeth of the 

 last segment remind us of 0. costalis. Curt., but they are more slender, 

 and stand a little more dorsalward, similar to the triangular production 

 of the same segment in O. falcata. It is very interesting that the 

 genus Oxyethirn, as also other genera of Hydroptilido), which show 

 great constancy in the pattern of colouring and neuration, have such 

 strong differences in the anal parts. 



In May very common on the "Zlufa Stoka'' in Trebon. 



EXPLANATION OF THE FIGURES. 

 Anal parts of Oxyethira tristella, Kip., ^ . 



A — from below, x 210. B — from side, x 210. C — from above, x 160. 



Trebon, Bohemia : June Isl, 1895. 



ON NEW AND OBSCURE BRITISH SPECIES OF BIASTATA. 

 BY R. H. MEADE. 



Having been laid up by a long illness I have been unable to 

 notice some remarks made by Mr. Verrall at p. 8» in the number of 

 this Magazine for April, 1894, respecting some species of Diastata 

 recorded as new to Britain by Mr. Beaumont in the previous number, 

 which had been named by me. With respect to the first named 

 species, D. obscurella, Flu., this was evidently mentioned by an over- 

 sight, as it had been described long before as British by Walker in 

 the "Insecta Britannica," and included by him in the genus Diastata, 

 though it has been now restored to that of Geomyza by Mr. Verrall. 

 The specimen which I named D. hasalis, Mgn., was an imperfect 

 example, in which the wings were damaged, and I could not see the 

 characteristic marks denoting D. notata, to which species it probably 

 belonged. The abdomen in both cases is described as being yellow or 

 translucent at the base, whence my mistake. The species which I 

 called D.fumipennis, Mgn., may probably be the same as D. nigripennis, 

 Lw., but I do not know that species, and have not met with liuw'- 

 description of it, neither is it recorded in Mr. Virrail's li.sts. 



