Fly: Haltere

Curvier and crisper in large ("L").

Grrr, a beautifully sunny day but I was stuck inside for most of it! I took advantage of my lunch break, and had a quick macro session in the foliage in the garden. I found lots of flies and not much else, so here's a fly...

The little yellow drumstick-shaped appendage visible behind the "knee" of its second leg is the haltere: these are modified (highly reduced) wings found in all dipteran flies (Diptera: di = two, ptera = wing. So called because most insects have two pairs of wings, but dipterans only look like they have one pair because their second ones are so shrunken...). The halteres flap up and down in flight acting as stabilising devices and have sensory organs at their bases (campaniform sensilla, which makes them function rather like the gyroscopes used to establish orientation in aircraft...). They stick out from the thorax at a 45 degree angle such that they are orientated at right angles to each other which maximises the orientation information that they provide.