Miller. — The Diptera Fauna of New Zealand. 291 



R 4 + , 5 and M 4 , the latter running almost parallel with the wing-margin ; 

 basally cell R 5 is closed by the cross-vein r-m, which is more or less 

 oblique, longer or shorter, and situated before, near, at, or beyond the 

 middle of cell 1st M 2 . Intersecting the lower part of the cross-vein r-m 

 and running through cell R to end in cell R- close to the vein M 1 + 2 is a 

 more or less developed — though sometimes absent — spurious vein charac- 

 teristic of the family: this is the vena spuria. Basally the vena spuria 

 may be evanescent, but otherwise arises from the origin of vein R 2 + 3 

 usually in those forms where the cross-vein r-m lies before the middle of 

 cell 1st M 2 , or, where this cross-vein is beyond the middle of cell 1st M 2 , 

 the spurious vein originates from the vein M where the latter curves 

 downward to meet vein Cu at the base of the wing. A little before 

 r-m in cell R the vena spuria is swollen knob-like, from whence a vein- 

 like stump may descend either to evanesce or unite with vein M, or a 

 spurious cross-vein may connect the vena spuria above with the vein 

 R 4 + 5 near the origin of the latter, which is then somewhat angulated 

 at this point. The vein M, just beneath the swelling of the vena spuria 

 and behind the cell 1st M 2 , is frequently sinuated ; from the origin of 

 this sinuation in some species (fig. 27) an indistinct vein arises perpen- 

 dicularly into cell M and turns abruptly forward, crossing into cell 1st M 2 . 

 The veins M t and M 2 are united for the greater part of their length, 

 branching near the wing-margin, the anterior branch, M l5 closing the cell 

 R 5 as already noted ; M 2 may either continue beyond the fork or be 

 confluent with M 19 which in some cases is angulated, giving rise to a 

 short stump into cell R 5 (fig. 22). Connecting the veins M and Cu x + M 3 

 is the cross-vein m running more or less parallel with the wing-margin 

 and meeting vein M either before the branching of M x in such forms 

 where M 2 is continued toward the margin, or at the fork of M t where 

 M 2 is confluent with M t . As with vein M 2 , the vein Cu 4 -{-M 3 is either 

 confluent with the cross-vein m or is continued beyond toward the margin ; 

 owing to the fusion of the veins Ciij and M 3 , the cross-vein m-cu is 

 eliminated. After the confluence of Cu 2 and 1st A, Cu 2 -f- 1st A either 

 runs straight to the margin or is more or less prolonged and curved. In 

 cell Cu 2 of most species is a distinctly developed vein arising at the origin 

 of 1st A and, running close to vein Cu, ending beyond the middle of the cell. 

 The basal " vein " of the alula is connected with the origin of Cu by a distinct 

 cross- vein and the arculus between Cu and R, or M and R, is well developed. 

 According to the venation, the species discussed below form three groups. 

 In the first (Plate XL VII, fig. 6) the costa ends with vein R 4 + 5 at the apex 

 of the wing, which is more or less blunt ; the vein R 4 + 5 is practically straight 

 above cell R 5 , and the veins Cu 4 + M 3 and M 2 are more or less developed 

 beyond the cross-vein m and the vein M t respectively ; also the cross-vein 

 r-m is before the middle of cell 1st M 2 (Syrphinae). In the second group 

 (figs. 3 and 4), the costa ends before the apex of the wing, which is more 

 or less pointed; the vein R 4 + 5 is gently curved into cell R 5 , the veins 

 Ci^ + M 3 and M 2 are confluent with the cross-vein m and the vein M x 

 respectively, and the cross-vein r-m is near or beyond the middle of cell 

 1st M 2 (Milesiinae). In the third group (fig. 1) the costa ends distinctly 

 before the apex of the wing, which is pointed ; the vein R 4 + 5 is deeply 

 curved into cell R 5 ; the veins C^ + M 3 and M 2 as the second group ; 

 the cross-vein r-m beyond the middle of cell 1st M 2 . A further reduction 

 occurs in this group (Plate LI, fig. 3) in the closing of the cell R t of 

 some species by the confluence of veins R x and R 2 + 3 (Eristalinae). 



10* 



