Figure 2

(a) A splined fly wing. Colored lines indicate spline approximations to the veins in the wing; arrows indicate user-defined landmarks required for the splining procedure (see Houle et al., 2003, for details). (b) Landmarks defined by wing–vein intersections and used for distance measurements. Intersections 0, 6–10, 15 and 16 were deemed too prone to measurer bias or inaccurate estimation for use in the present study.