DIPTEROUS TRIBE OF SPJLEROCERID.E. 33S 



fewer bristles ; 2d joint of hind feet shorter : wings blackish : 

 base of the costal nerve less bristly, 2d ending half way between 

 the 1st and 3d ; cross nerves not so distant. (Length § ; wings 

 U line.) 



Common in the same situations with No. 6. 



AA. Antennce in latera aversce* 



B. Oculi nudi. 



C. Areola marginalis costara mediam superans. 



Sp. 19. L. zosterae. Nigra opaca alls infumatis. 

 Borborus zosterse, Ent. Mag. I. 178. 



Opaque black : front gibbous, bristly : face much elevated between 

 the antennae, which are turned in opposite directions, lying close 

 to the eyes ; their 2d joint is very bristly, and larger than the 3d : 

 the arista thickly pubescent, the pubescence whitish : thorax 

 scarcely pubescent, very flat, with an impressed line down the 

 middle : scutel not as long as the metathorax ; glabrous, with 

 four bristles, as also in those which follow : legs rather short, 

 thinly hairy, piceous, with the knees and feet tawny, or entirely 

 tawny : middle shanks armed with numerous bristles : 2d joint of 

 hind feet not very long, scarcely thickened : poisers with a deep 

 brown knob : wings of a brownish yellow, the nerves of the same 

 colour ; costal more dusky, rather thick, bristly at the base ; 2d 

 nerve extending little more than half way between the 1st and 3d: 

 intervals of the cross nerves considerably longer than the principal 

 one. (Length 1| ; wings 3 lines.) 



There is a variety scarcely a third that size, but differing so little in 

 other respects, that I cannot consider it a distinct species. 



Common on sea-weed: Mr. Walker has found it near 

 London ; and also in the Isle of Wight, Cornwall, and North 

 Wales. 



Sp. 20. L. leucoptera. Nigro-fusca, alls albis, costa nigri- 

 eante. 



Dusky with paler legs : eyes small : arista with thick whitish 

 pubescence : scutel short, nearly semicircular : middle shanks 

 bristly ; 2d joint of hind feet long and scarcely thickened : poisers 

 brown : wings whitish ; the costal nerve and those next to it 

 dusky, the rest colourless ; the costal region dusky towards the 

 end : costal nerve with a few bristles at the base, a little thickened 

 from the 1st to the 2d main nerve ; the latter ending much 

 nearer to the 3d ; marginal cell long and very narrow ; sub- 



