| Abstract: | In the Siphonini (Diptera: Tachinidae), crossvein dm-cu is relatively near the wing margin (the primitive condition within the tribe) in larger siphonines and displaced toward the middle of the wing (derived condition) in smaller siphonines. Displacement of dm-cu increases the passively deformable area of the wing relative to the supporting area, presumably increasing the aerodynamic efficiency of flight in smaller siphonines. The trend toward increasing the passively deformable area in smaller siphonines compared with larger ones is complementary to the general trend toward reduced venation in tiny insects. |
