172 BR. J. ENT. NAT. HIST., 6: 1993 



setae. Geomyza denigrata and G. adusta Loew have only vaguely darkened wing tips 

 and neither crossvein darkened. 



Genuine specimens of breviseta seen by me come from Kent (Folkestone), Wiltshire 

 (Coombe Bissett), Cambridgeshire (Barnack Hills and Holes NNR) and South 

 Yorkshire (Pieces Bank). The species has been pooted from tussocks of Poa 

 trivialis L. on limestone grassland which was lightly grazed by sheep, swept 

 from moderately tall, slightly calcareous grassland and caught in pitfall traps set 

 in ungrazed chalk grassland. Based on this evidence, it may be restricted to calcareous 

 grassland. 



Geomyza hackmani Nartshuk, 1984. Vockeroth (1961) and Chandler (1991) 

 have pointed out that there is a second species of "combinata" here besides 

 balachowskyi though Nartshuk's name and description of the second type appear 

 to have been overlooked. Separation from balachowskyi can be made reliably 

 only on the basis of the male genitalia. The ground colour of the postnotum in the 

 eleven males seen by me is conspicuously darker than the rest of the thoracic 

 dorsum although it is quite heavily grey-dusted. Until a much larger sample is 

 checked, it would not be wise to use this character by itself or to assume that 

 females may be identified using it. Because of the confusion, hackmani has probably 

 been overlooked but it seems to be genuinely uncommon. It has been found in 

 grasslands on alluvium, limestone, neutral clay and on freshwater and slightly brackish 

 coastal grazing marshes. There are records from Surrey, Oxfordshire (Vockeroth, 

 1961), Greater London, Cambridgeshire, Worcestershire, Gwent, Cumbria and 

 Aberdeenshire. Dates of capture range from early July to early September. 



Geomyza hendeli Czerny, 1928. Czerny described this species from one female with 

 its legs missing. Hackman (1958) concluded that it was just a small form of apicalis, 

 because the wing pattern and shape were the same in both species and apicalis some- 

 times lacks the small postsutural dorsocentral seta and so resembles hendeli. Martinek 

 (1978a) considered hendeli to be a good species, but a male and two females that 

 Dr Martinek lent to me look very much like apicalis. These have very small post- 

 sutural dorsocentral setae although they are still discernible. Geomyza hendeli was 

 added to the British list on the basis of a male (in the Natural History Museum) 

 identified by Collin (1945). Its genitalia are identical to those of apicalis, its thorax 

 is 0.98 mm long, its wing is 2.13 mm long and the wing's breadth is 20% of the length; 

 these dimensions are well within the range of variation of apicalis (Table 1). I consider 

 this specimen to be a not particularly small specimen of apicalis. Two other specimens 

 labelled hendeli in the Natural History Museum are typical apicalis, one having a 

 small postsutural dorsocentral seta on one side and genitalia that are indistinguishable 

 from those of apicalis. Two females, from Wicken Fen, Cambridgeshire (I. Perry) 

 and Dungeness, Kent (R. K. Morris), completely lack a small postsutural dorsocentral 

 seta. They closely resemble apicalis, but features which may be trivial, that are found 

 only in extreme examples of apicalis, are the dark brown occiput which is usually paler 

 or patchy brown in apicalis, clearly defined dark notopleurae which are often only 

 indistinctly brown in apicalis, and, on the dorsum of tergites 2-4, conspicuous marginal 

 setae which are often not clearly larger than other setae in apicalis. I have not seen 

 another specimen ascribed to hendeli from Holme, Norfolk (1983) collected from 

 dunes which are frequently the habitat of apicalis. Thus, although the identity of hendeli 

 is far from satisfactory, it would be prudent to retain the name for specimens that 

 completely lack a small postsutural dorsocentral seta until a series of males can be 

 compared with apicalis. 



