Little blueish fly! Prosopomyia pallida
Let me introduce a little 5 mm and friendly fly, with reddish and blueish hues, which was wandering along the back of a bench. It saw me and moved away from me –walking, not flying- several times. Called Prosopomyia pallida, it belongs to the family Lauxaniidae. Flies from this family live in wooded areas, and this kind of area is present in the first arrondissement of Lyon!
On the lateral view, the white excrescence near the junction thorax/abdomen is the left halter, a wing-derived structure substituting the second pair of wings. It’s a characteristic of the order Diptera. Thanks to rapid oscillations, it stabilises the fly of the flies. Another order has developed halters, the Strepsiptera, but this time halters substitute the first pair of wings!
Last update: 07/09/2020