Cross-vein density in the nodal region correlates with hunting strategy across 5,700 described Odonata species.
One opaque cell at the leading edge prevents aeroelastic flutter at wingbeat frequencies above 30 Hz.
Fraser’s 1934 plates remain the taxonomic reference for Calopterygidae — the pinned holotypes have faded.
Of 14 nodal characters mapped by Tillyard, three discriminate reliably. The rest collapse under convergent evolution.