BRITISH SPECIES OF DIPTEROUS GENUS FANNIA 135 



and the preapical one, smaller, near the tip, one antero- 

 dorsal bristle about the middle, and one antero-ventral 

 bristle. The expressions used to designate the surfaces of 

 the leg areas were introduced by Mr P. H. Grimshaw, and 

 are arrived at by considering the leg as placed at right angles 

 to the body. It will be unnecessary to mention the bristles 

 enumerated above in the description of every species, but 

 when their position or number departs from the usual rule, 

 note is made of this fact. The wings of the $ are not so 

 pointed as in the £ , the third and fourth veins are not so 

 distinctly convergent, and although the wings may be 

 browned in the £ , they are nearly always clear in the ? . 

 In most cases the descriptions in this paper have been taken 

 from British specimens, but I have been unable to obtain 

 examples of Kowarzii, Verr., umbrosa, Stn., glaucescens, Ztt., 

 parva, Stn., and the doubtful vesparia, Mde. 



I have to thank Mr A. E. J. Carter for the loan of a 

 number of specimens of the genus to assist me in drawing 

 up descriptions, and Messrs J. J. F. X. King and A. Ross for 

 much assistance in various ways. 



I have not adopted the character used by Stein to 

 separate the groups in his table by means of the size of the 

 calyptra, because I find that with set specimens it is 

 impossible for a beginner in the study of the group to say 

 with certainty to which section a specimen belongs. In fact, 

 I find that when the calyptra are said to be equal in size, the 

 under scale is generally the smaller. I have therefore 

 adopted a new system, which may or may not have other 

 advantages, but I hope that in keeping clear of what I 

 consider a disadvantage I have not added others. 



In this group, as in others, one finds occasionally 

 specimens that refuse to work out by the tables given for 

 the known species. This is more often the case with females 

 where the bristling of the legs, etc., is taken as the guide. 

 There are several specimens of this kind before me just now 

 which illustrate this fact. It is quite possible, nay probable, 

 that they belong to undescribed species. I prefer, however, 

 to allow them to remain in their present condition of 

 uncertainty, to making a new species from a female that 



