Old Wings; New Wings

Close up of the eyes of a libelullid dragonfly (College Station, TX).

This is a libellulid dragonfly, or common skimmer.  The family name Libellulidae probably comes from the latin word ‘libella’ meaning ‘booklet’ (interestingly, the spanish word for dragonfly is libélula).  This is in reference to the wings:  paleopteran insects (dragonflies, damselflies and mayflies) have wings which are controlled strictly by direct flight muscles and held folded up over their backs.  Neopteran insects are able to twist their wings and fold them flat along their backs.  This development allowed insects to branch into many new habitats that would not have been conducive to managing large delicate wings.  Think of beetles which burrow into bark or cockroaches which scurry under doors.  Today, 99% of all insect species are neopteran.