Wing of female of Physocephala texana from McAlpine (1981, fig. 53) [1]. Abbreviations are as follows:

Veins:

A1 = Anterior (or 1st) anal vein
A1+CuA2 = vein formed by fusion of veins A1 and CuA2
CuA1 = 1st anterior branch of the cubitus
CuA2 = 2nd anterior branch of the cubitus
M1 = 1st (posterior) branch of the medial vein
R1 = 1st branch of the radial vein
R2+3 = branch formed from fusion of the 2nd and 3rd branches of the radial vein
R4+5 = branch formed from fusion of the 4th and 5th branches of the radial vein
Sc = subcosta

Cells:

bm = basal medial cell
br = basal radial cell
cup = posterior cubital cell
dm = discal medial cell

cross-veins:

r-m = radial-medial cross-vein
sc-r = subcostal radial cross-vein

References

1. McAlpine J.F.
   (1981) Key to Families - Adults. in: McAlpine J.F. (Ed.), Manual of Nearctic Diptera. Agriculture Canada, Ottawa, pp. 89-124.