Early Eocene

Green River Formation, Parachute Creek Member

Near Bonanza, UT, USA

Crane fly, fly and mosquito on shale. All are fair to good.

Insect, Arthropod.  Association.

This specimen is an interesting and affordable association piece for the novice or casual science enthusiast.

Crane flies, flies, midges, and mosquitoes belong to the Order Diptera which includes over 120,000 species.  As the name indicates, dipterans are considered two-winged forms though they also bear a pair of halteres which have been interpreted as a vestigial second pair of wings (likely functional in an ancestor) that serve as balancing organs during flight.

Not all “flies” are true flies.  Dragonflies, butterflies, caddisflies, and snakeflies all belong to separate orders of insects and are only very distantly related to flies.  It’s just a matter of similar common names.

Flies appeared by the Middle Triassic and diversified across the rest of the Mesozoic.  They survived the K/T extinction and diversified again during the early Cenozoic.