10. BERIS 205 



Wings mucli paler than in the male, and rather yellow about the base but 

 not so much so as in B. chahjheata ; stigma much more conspicuous. Squamae 

 paler, being more brownish yellow. Halteres yellow. 



Length about 6 mm. 



This species varies but little (unless the specimens I have described as 

 B. fuscipes are only varieties) though a considerable number of specimens 

 taken by Colonel Yerbury at Porthcawl in June and July 1906 have more 

 intensely black wings and legs, the pale base of the wings becoming thereby 

 more conspicuous, while the pale knees and ankles almost disappear; it is 

 remarkable that other species of Boris taken at that time at Porthcawl also 

 possess more intensely blackened wings. It may be easily distinguished from 

 B. chalyheata by the more brilliant green thorax, the less produced longer 

 and narrower face, the more pointed antennae, the yellower knob of the 

 halteres, the pale pubescence down the sides of the abdomen of the male, 

 the much blacker legs in both sexes, the more equally dilated basal joint of 

 the hind tarsi in the male, the blacker basal joint of the hind tarsi, the 

 longer abdomen, the larger size, and the narrower frons of the female. 

 From B. fuscipes (as I interpret that species) it is distinguished by the 

 longer third joint of the antennae, blacker legs, and less parallel -sided frons 

 of the female, but more details of distinction are given under B. fuscipes. 



B. geniculata is not at all common in Britain and I possess recent 

 records from only Warwickshire, (Sutton), Herefordshire (Tarrington), 

 Glamorgan (Porthcawl), Denbigh (Llangollen), Durham (Bishop Auckland 

 and Hesleden), Edinburgh (Inveresk), Perth (Eannoch), and Sutherland 

 (Golspie), though old records include Yorkshire (Hebden Bridge) and 

 Ireland. My dates extend from June 20 to August 1. Mr A. E. J. 

 Carter has taken both this and B. chalyheata at Inveresk and found B. 

 chalyheata fairly common in May and June, while B. geniculata occurred 

 more rarely in August and September, so that it appears to be a later species 

 than B. chalyheata ; Colonel Yerbury has noted that the males (at Porth- 

 cawl) dance in the shade, and have a wild flight like a Rhamphomyia. 



Synonymy. — I accept the name given by Haliday for this species in Curtis' 



British Entomology, PI. 337 (1830) because I consider it the earliest certain nanae, 



but the utmost confusion has arisen between this species and B. fuscipes Meig. 



(if they are distinct). Haliday appears to have known his species well in both sexes 



and to have taken numerous specimens, as Curtis recorded it as being in his own and 



other cabinets, while the descrii^tion and figure given are unmistakable. At that 



time B. fuscipes was comparatively ignored because its eight-spined scutellum was 



considered a good specific distinction. Meigen (1820) described B. fuscipes from an 



English male sent him by Dr Leach, and used the words " pedibus fuscis : tibiis 



" basi flavis " which clearly distinguish it from B. chalyheata, and "Fuhler...nicht 



" ganz so lang als der Kopf " which along with " pedibus fuscis " applies better to B. 



fuscipes (as I interpret it) than to B. geniculata. Macquart's descriptions of B, 



fusciijes are evidently compiled from Meigen's and are valueless. Next Loew in 



1846 when describing B. fusci2)es said of the male "Fiihler erheblich kiirzer als der 



" Kopf... die Behaarung des Hinterleibes ist schwarz'" (which does not apply to 



the longer and more conspicuous pubescence on the sides of B. geniculata)...^'' Die 



" Beine sind schwarzbraun, die iiusserste Spitze aller Schenkel und Schienen, so wie 



" die Wurzel der letzteren in etwas grosserer Ausdehnung gelblich gefarbt ; an den 



" Vorder — und Mittelbeinen zeigt die Wurzelhalfte der Metatarsen dieselbe, oder 



" doch eine nur wenig dunklere Farbung ; die Metatarsen der Hinterbeine sind 



" merklich langer als die 4 folgenden Glieder zusammen, ziemlich stark verdickt, vou 



" braunlicher Farbe, die aber auf der Oberseite, wegen der dort befindlichen ganz 



" kurzen schwarzen Behaarung ein schwarzbraunes Ansehen bekommt ; ... Die 



" Schwinger sind schwilrzlich," (this colour of the halteres is wrong) ; and of the 



