Contents

14 June 1985
Vol 228, Issue 4705

About The Cover

Shadowgraph of a dragonfly, Aeschna palmata. The slender body and intricate wing venation of the dragonfly reflect millions of years of evolutionary pressures. Such structures support remarkable aerodynamic agility. Unsteady, separated fluid mechanisms appear to produce the high lift needed for this agility. See page 1326. [Wolfgang Bank, University of Colorado, Boulder 80309]