3. OXYCERA 93 



whitish pubescence, and the pubescence becomes rather longer on the black 

 sides of the mouth ; back of the head inflated to half the length of the eye, 

 orange except on a long black streak against the upper third of the eye, and 

 glossed with silver on all the lower part ; absolute back of the head black ; 

 pubescence very short and all pale. Eyes small ; facets all eijual. 



Thorax with the yellow line from the humeri usually rather wider and 

 more connected and more conspicuous than in the male, and the spot on the 

 sternopleurai larger. Pubescence on the thorax and scutellum more con- 

 spicuous. 



Abdomen with its margin all yellow from the middle of the second 

 segment to the tip and widening out on the third and fourth segments but 

 very narrowly connected with the ti]!. Belly with a small yellow spot on the 

 middle of the base of the first segment, and yellow on most of the middle of 

 the second segment, and on the hindmargins of the third, fourth, and fifth 

 segments. 



Legs orange with a broad shining brown or blackish (sometimes incom- 

 plete) ring on all the femora a little before the middle ; coxa? and trochanters 

 paler than in the nrale, but the rest of the legs as in the male. 



Wings as in the male. Squamaj and their fringes paler. 



Length about 3 mm. 



'o^ 



This species is easily distinguished by its simple cubital vein and its 

 partially darkened legs and scutellum; it varies a good deal in the extent 

 of black coloring on these parts and on the frons of the female, but not 

 to such an extent as to cause any doubt. Its nearest ally is the next 

 species, 0. nigripes, but that is a larger and more squarely built species 

 besides being much blacker. 



0. p2/f/ma:a is probably the commonest of our small British species of 

 Oxycera, but yet is decidedly local though abundant in its localities. My 

 records are limited to but very few counties, but Curtis and Dale recorded 

 it from various localities in South Dorset, and Curtis stated that it was 

 common at Seaton in Devonshire ; Colonel Yerbury has taken it in Woolmer 

 Forest in Hampshire, and he and Dr Wood have of course found it 

 abundantly in various localities in Herefordshire, whilst I found it in 

 numbers at Tuddenham Fen in Suffolk; the Eoyal Scottish Museum 

 possesses it from Aberlady in Haddington, and if 0. nigripes is only a form 

 it has occurred near Inchnadamph in Sutherland. The records extend from 

 June 22 to July 20. Dr Wood considers that it prefers the wettest parts 

 of small bogs. It is recorded from South Sweden to Austria. 



Sytwnymy. — This has been very commonly called 0. muscaria Fabr., because of 

 Meigen's mistake_ (Syst. Beschr., iii., 346) in stating that they were synonymous, 

 l)ut 0. muscaria is now considered to be a very distinct South European species! 

 The var. ajfinis of Dale has I believe never been described, and it is possible that 

 my 0. nigripes may l)e only a strongdark northern form, though at present I 

 prefer to retain it as distinct because of its larger size and squarer build. 



3. O. nigripes Verrall. Cubital vein not forked. Scutellum all black. 

 Legs black with only the knees orange. Larger than 0. jyyu'mcva. 



Very much like 0. ijygmwa but rather larger and stouter, 

 and altogether much blacker (figs. 84, 101). 



$, . Head longer in proportion to depth when seen in profile, and comparatively 

 broader when seen from in front, than in 0. pi/gmcea. Face with the black 

 middle portion more defined, and the lower margin of the eyes running less 

 straight from the pufted-out lower part of the back of the head to the front ; 

 upper part of the back of the head less hollowed out from the eyes. Eyes less 

 round, touching for a short distance, almost bare ; facets separated in size as 



