290 



LEPTID.^ 



half of the hind femora ; even the spurs (which in form are the same as in 

 A. Ibis) quite black ; pubescence on all the femora fairly abundant ; "touch- 

 hairs " beneath the front tarsi unusually numerous even uj) to the last joint. 

 The outer pulvillus and claw of the front tarsi distorted as in A. Ibis. 



Wings blackish with conspicuous hyaline markings (fig. 192) and the 

 apical quarter rather faded out and the posterior portion still more so ; two 

 incomplete pellucid bands cross the wings, the first one just before the middle 

 beginning beneath the subcostal vein and extending irregularly downwards 

 but not to the hindmargin and having the end of the second basal cell 



^3r^;*S©' 



Fio. 192. — Atherix marginata S- x 10. 



conspicuously hyaline, the second one forming an interrupted fascia about 

 half-way between the first one and the tip of the wing; stigmatic space 

 entirely blackened right up to the tip of the marginal cell. Squamaj (alar) 

 blackish, with a faint pale fringe which is longer but much sparser than 

 in A. Ibis and which may perhaps be in a single row. Hal teres blackish, 

 base of stem rather brownish. 



? . Very much like the male. Frons about one-quarter the width of the head 

 and bearing a deep middle channel, moderately shining black, with slight grey 

 dust about the sides and surrounding the base of the antenme ; pubescence 

 on frons all black, fairly abundant but not dense, absent on the grey sides 

 and down the middle channel ; when viewed sideways the vertex and frons 

 appear much more extensively grey ; side-cheeks with the pubescence pale 

 on their upper part but black below and then continued in a single line under 

 the eyes, and behind this line the wide jowls and the bottom of the head bear 

 long fairly dense dull yellowish white pubescence, which grows shorter up 

 the lower half of back of the head, leaving the actual margin against the 

 eyes bare ; above the middle of the back of the head the pubescence is rather 

 short and the bristly black hairs are not so sharply contrasted with the 

 longer pubescence on the vertex as in the male. 



Thorax with shorter, sparser, and more recumbent pubescence which is 

 pale with a few inconspicu.ous black hairs intermixed. 



Abdomen with the seventh segment and the ovipositor forming a short 

 black triangle. 



Legs with pale pubescence on the coxae, and with the pubescence on all the 

 femora shorter ; " touch-hairs " beneath the front tarsi very numerous. 



Wings more hyaline about the base, and the costal cell only pale yellowish 

 brown. 



Length about 8 mm. 



This species can hardly be confounded with any other if attention be 

 given to its wholly black legs. 



A. marginata is rather local, but I know of numerous Devonshire 

 localities where Colonel Yerbury has often found it at the sides of streams. 

 It has also occurred in the New Forest commonly on Alders (Alnus 

 glutinosa), and at Barmouth, Eydal, and according to J. F. Stephens near 

 London, while Curtis mentioned Darenth. Colonel Yerbury has also 

 taken it in Ireland at Waterville and Kenmare. The dates range from 

 June 10 to Aucrust 26. From the abundance of the "touch-hairs" 



