1886.] 157 



the prsefurca being considerably before the end of the mediastinal. 

 The smallest British species, being slightly smaller than D. morio ; 

 brownish-black, somewhat shining, a pale line between dorsum and 

 pleurae, the whole disc of the abdomen with a lurid yellowish tint. 



<J . Antennae all black, basal joint shortish, joints of the flagellum oval, bearing 

 bristles nearly three times as long as each joint ; palpi black ; rostrum shining 

 blackish ; frons and vertex blackish-brown, with grey reflections of tomentum. 

 Halteres brownish-black, yellow at base. Pleurae with yellowish reflections and 

 greyish tomentum. Genitalia dark yellowish-brown at the base, becoming nearly 

 black at the end, the basal lamellsB simple externally, inside at end above is the 

 usual hooked process on each, on which are two long diverging bristles, yellowish- 

 brown at their base ; outer lamellae smallish, ending above in a strong curved spine ; 

 middle piece long, dark yellowish ; sometimes it appears as if the end of the basal 

 lamella, or the base of the outer lamella, had (when seen sideways) two curved 

 spines above, and the outer lamella a long almost straight one below, hence it is 

 evident that the hook at the end of the outer lamella originates near the base of the 

 lamella and can be unfolded. Legs blackish, lurid at base, end of femora (especially 

 front pair) rather thickened ; coxae and trochanters yellow. Wings smoky, extreme 

 base yellow, stigma distinct, almost blackish to the naked eye ; veins on the outer 

 half of the wing pubescent, bearing rather long hairs. The mediastinal vein and its 

 subcostal cross vein end in what looks like a short fork rather beyond the middle of 

 the praefurca, the dark stigma is elongate-oval, at its end are the end of the sub- 

 costal vein and its marginal cross vein, both very faint, the cross vein is considerably 

 the longer and bent downwards, making the end of the subcostal appear like a short 

 cross vein to the costa ; the marginal cross vein joins the upper branch of the radial 

 at about one-third the length of the latter ; the praefurca is more than half the 

 length of the forks of the radial ; all the veins near the tip of the wing curve down ; 

 the discal cell is always open and coalesces with the second posterior cell, making 

 the discal vein forked ; the bases of all the posterior cells are nearly level, the sub- 

 marginal being only a little nearer the base of the wing ; anal vein a little incurved 

 at its end. 



$ . Yery similar to <? , but the base of the legs a little paler ; ovipositor reddish- 

 yellow. 



This species is evidently closely allied to D. pilipennis, Egger 

 (= L. turpis, Wlk.), but is easily distinguished by its smaller size, 

 open discal cell, and by the disc of the wing on its outer half not 

 being pilose ; it appears a little like D. morio, but is really very dis- 

 tinct ; I find a L. aperta, Lw., next to L. morio in Verh. z.-b. Wien, 

 xxiii, 27 (1873), but I cannot trace any description. 



Common near the Falls of the Shin in Sutherlandshire, from July 

 11th to l7th this year, near the water on the damp sides of cliffs, and 

 more sparingly at other similar places, also on the Eoss-shire side of 

 the Oykel. 



D. pilipennis : Egger's description was published in Verh. z.-b. 



