#small-headed fly

here is a small-headed fly, Astomella hispaniae, a ridiculous beast that i distinctly remember finding at like 8 in the evening because the accursed sun wouldn't let me go outside until then. i was reminded of my first encounter with this weird little family by apsciencebydan's recent post and i can confirm they're very disorienting to see in person, since as i was approaching it i thought it was a decapitated hoverfly for some reason

Velmi vzácný druh z řádu dvoukřídlých a čeledi Acroceridae. Byla zastižena na letišti v Hradčanech na Českolipsku. 

Photo by Catherine John, in Ballarat, Victoria

One of the great things about the proliferation of smartphones, and especially the ones with decent macro lenses, is you get a vast increase in the number of photos of obscure invertebrates. Actually getting a correct ID on them is another thing, but I’ve talked with various experts and they agree that it’s gratifying to see how many amateurs are actually interested in this sort of thing, and post them to relevant Facebook groups.

Cyrtus gibbus female trying ovipositing on the vial

Probably an Ogcodes sp. Spotted by Liz Rowe, but she didn’t give me a location.

Small-headed or Hunchbacked Flies are distinctive-looking, with tiny heads and almost globular abdomens, and many species resemble bees for their own protection. Most of the 500-odd species are poorly known, from 10 specimens or less, because they’re most often found when a spider is brought in for study, and it turns out it was parasitised by Acrocerids. 

Small-headed flies lay thousands of tiny eggs - quite often on clotheslines for some reason - and the minute maggots hurry off in search of a host. The larvae resemble tiny inchworms, and can jump. If they find a spider they grab hold, crawl up the leg to its body, and force their way through the body wall, usually at at the thinner exoskeleton at a joint. Often, it lodges near a book lung, where it may remain for years until emerging again to pupate outside the host.