Fig. 9. Cartoon showing the aerodynamic features of a Class II LEV in the flow around the wings and thorax of Manduca sexta in late downstroke (top). DPIV inserts (bottom) show typical flow fields at each location with a freestream of 3.5 m s^-1. The midwing insert (left) has simple (horizontal) freestream subtraction; the centreline insert (right) has local freestream subtraction of 3.5 m s^-1 angled 1° below horizontal.