Thanks to a sharp-eyed Naturally Curious blog reader, a recently mis-identified active winter insect can be correctly identified. What I referred to as a “snow scorpionfly” last week was, in fact, a type of crane fly that, as an adult, has no wings. Like snow scorpionflies, these wingless snow-walking crane flies appear on top of the snow on warm winter days. These two kinds of insects are also very similar in shape and size, but, unlike snow scorpionflies, this group of crane flies have what are called halteres, knobbed filaments which act as balancing organs (see photo).
Scorpion snowflies, despite their name, are not true flies in the order Diptera. Crane flies are. Most species of true flies have one pair of wings, instead of the usual two that winged insects have, as well as halters, which take the place of hind wings and vibrate during flight. While wingless snow-walking crane flies lack a pair of wings, they do possess halteres, which are the key to distinguishing between a wingless snow-walking crane fly and a snow scorpionfly, which lacks them! (Thanks to Jay Lehtinen for photo I.D.)
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