168 [J«iy> 



7 (8) Outer lainelliJD elongate lancet-shaped, with long (in some lights) pale 



pubescence; antennae long 3. auctum'Liw. 



8 (7) Outer lamellao broad lancet-shaped, with short black pubescence ; antennae 



comparatively short i. lanceolatum Lw. 



9 (4) Hind femora without a prcapical bristle. 



10 (11) Inner lamellae ending in a long, simple, curved, pale hair... 



5. caliginosum Meig. 



11 (10) Inner laracllse ending in a long, compressed, slightly curved thread, which 



breaks into a ciliation at its tip 6. appendiculatum Zett. 



12 (1) Frons glossed with white ; coxae without any black bristles ; hind femora 



with a preapical spine. 



13 (14) Front tibiae with a spine and a tiny ciliation beneath, the spine being just 



below the middle and rather turned back ; outer lamellae short... 



7. brevicorne Curt. 



14 (13) Front tibiae almost bare beneath, and, at any rate, with no distinct spine ; 



outer lamellae long, hairy, and dilated at base 8. fissum Lw. 



Several more species should occur in Britain. A small species 

 occurs in Norfolk amber. 



1. X. fasciatum Meig. : very distinct in the male, because of its 



yellow abdominal markings. Not uncommon at Tongue (on 

 the North Sea) in June, 1886, and Col. Terbury took it at 

 The Mound in Sutherland in June, 1901. 



2. X. ononotrichum Lw. : occurring from the New Forest to Tongue, 



but apparently more common in the North than in the 

 South. 



3. X. auctum Lw. : I first recorded this as British from a male taken 



near Lyndhurst on June 23rd, 1873, and I think a male 

 taken by Col. Yerbury at Ledbury in Herefordshire on 

 July 12th, 1902, is the same species. The specimens are 

 quite distinct from the other seven British species, but their 

 positive identification with Loew's species must await 

 further proof, because I can find no reference to the male 

 since Loew described the species in 1857 from Germany, 

 and in his description he says nothing about the coxal or 

 preapical bristles and only imperfectly describes the 

 lamellae ; my chief doubt is caused by the arista in the 

 British specimens being less than one-third the length of 

 the third antennal joint. 



