496 BOMBYLID^ 



whitish rather than tawny and merged into the similar pubescence on the 

 jowls. 



Abdomen similar to that of the male but the basal pubescence usually 

 more rufous taAvny and with a dorsal line (more or less interrupted) of short 

 but conspicuous (when seen from behind) silvery white pubescence on at 

 least the last three or four segments which sometimes extends back almost 

 to the base ; a thin row of long (longer than the tawny hairs) black hairs is 

 fairly obvious on the hindmargin (except at the middle) of the second seg- 

 ment, and still more numerous black hairs occur on the hind part of the 

 third segment, after which the fourth and fifth segments are more intensely 

 black haired and have more tangled long outstanding hairs of which a few 

 may sometimes be inconspicuously tawny ; anus (when visible) brown and 

 encircled mth a fringe of red-orange or yellow hairs strongly contrasting 

 against the dense short black pubescence on the short last abdominal 

 segment ; ovipositor also with a reddish orange or yellow fringe. 



Legs orange or pale yellow, leaving little more than the basal half of the 

 anterior femora black and even less (though indeterminately) of the hind 

 pair ; tarsi less blackened towards the tip ; coxaj with less dense black or 

 brownish black pubescence, and the femora with rather dense black to 

 brownish orange pubescence ; hind femora Avith the row of antero-ventral stiff 

 black bristles more numerous (ten to twelve) and extended more towards the 

 base, and the other l^ristles about the apical third also more numerous ; tibise 

 with the rows of small black sjiicules rather more conspicuous. 



Wings, squamee, and halteres as in the male. 



Length about 13 mm. ; but varying from 10 mm. to 14 mm. 



This species appears to vary but very little except in size, even though 

 it has a wide geographical range ; it can be distinguished from B. medius 

 and its allies by the conspicuous black pubescence on the hinder part of 

 the abdomen. The marginal spots on the wings are sometimes faint and 

 the two large ones especially may occasionally almost disappear; I have 

 noticed several female specimens in which the radial vein throws off a 

 short adventitious fork on the upper side almost level with the base of the 

 cubital fork ; I once took a remarkably small specimen near Uckfield 

 in Sussex (8 mm.). 



B. discolor is not uncommon in early spring in the southern half of 

 England, as I have taken it in Sussex (all large woods and even open road- 

 sides), Kent (Darenth, Folkestone, etc.), and Suffolk (my own garden), 

 while I have records from Devon (Plymouth and Tavy Valley), 

 Dorset (Glanvilles Wootton), Somerset (Bath and Bristol), Hants, Essex, 

 Cambs, Suffolk (Ipswich, Sudbury, and Felixstowe), Norfolk, Oxfordshire, 

 Berks (Emborne), Hereford (Tarrington), and Glamorgan (Porthcawl), from 

 March 15 to May 17. It never has been so common in my garden as B. 

 major and I have not seen it in recent years ; it is a magnificent hoverer 

 in sunny places in woods, and is then very difficult to catch, but when 

 attracted by low growing flowers or seen out in cool sunshine it is not 

 difficult to secure. It is recorded from all Europe except the North and 

 extends to the countries bordering on the Mediterranean (where it 

 is most abundant) but it is curious that while not uncommon in 

 England it does not appear to occur in Scandinavia, while B. medius is 

 common there but does not occur in England. B. medius, which has the 

 pubescence tawny or even pale yellow all round the abdomen, should still 

 be sought for in England. 



Synonymy. — This is now fully unravelled, though many old authors (including 

 Walker) persisted in calling it 7>. medius. 



