26 Syrphidae. 



subcostal cell is open, or in some groups ciosed ; cubital vein unforked 

 and thus only one cubital cell; the vein is either straight or nearly 

 so, or it is curved more or less evenly down in the first posterior 

 cell, or in some groups it is strongly looped ; instead of this loop 

 there may in a few cases be a veinlet stretching down in the first 

 posterior cell, somelimes issuing from an angular bend of the vein; 

 the medial cross-vein is placed above the discai cell in the middle or 

 nearer the base or apex; the discai vein is always bent upwards at 

 the end (a branch) and ending in the cubital vein, the first posterior 

 cell thus always ciosed; a discai cell always present and always 

 bordered below by the upper branch of the postical vein, thus in- 

 cluding the fourth posterior cell ; it is ciosed apically by a vein which 

 I take to be a branch from the discai vein; the two veins closing 

 apically the first posterior cell and the discai cell I term in the de- 

 scriptions the upper and lower marginal cross-veins (the latter in the 

 Dolichopodids termed the posterior cross-vein). Anal cell always long, 

 stretching near to the margin but always ciosed ; axiilary vein shorter 

 or longer, but generally weak. Between the cubital and discai veins 

 runs a vein, characteristic for the family, the vena spuria; it is not 

 in connection with the other veins neither at base nor at end; it 

 begins below the base of the radial vein, runs obliquely downwards 

 through the medial cross-vein and terminales at the lower apical 

 corner of first posterior cell ; sometimes it is abbreviated at or a little 

 behind the medial cross-vein; below the base of the cubital vein it 

 shows a more or less pronounced thickening or a curious interrup- 

 tion; the vena spuria varies much in strength and is sometimes very 

 weak, but in all Danish genera it is present; in a few foreign genera 

 (as Graptomyza) it may be quite wanting. The basal part of the 

 radial vein bears, at all events in most cases, fine bristles; they are 

 sometimes quite distinct, but are often so fine as to be detected only 

 with difficulty or under the microscope, and they are sometimes only 

 few in number.i A real stigma never present, but the apical part of 

 the mediastinal cell may be more or less darkened to black or there 

 may here be a darkened part; sometimes Ihe darkened part begins 

 below the apex of the mediastinal vein with a more or less distinct 

 transverse vein between the mediastinal and subcostal veins, termed 

 the stigmatical cross-vein. The axiilary lobe generally well developed 



1 My studies tend to show that these bristles are almost always present, except 

 in the Pipiza-group, in the species of which I never have detected them ; they 

 are, however, often imperceptible, few, or only present near the base; in the 

 descriptions of the genera I have mentioned them only when they are some- 

 what distinct. 



