Hammerhead fly, Richardia telescopica, Richardiidae by Andreas Kay
from Ecuador: www.flickr.com/andreaskay/albums
@moogleface that’s the best
thing is that they’re not! there are a bunch of different fly
families containing species that have evolved big dumb eyestalks due to runaway sexual selection.
the above species is in the family Richardiidae.
the one you’re
probably thinking of is Diopsidae, e.g.
there are also species in Ulidiidae that do this, e.g.
also in Platysomatidae, e.g. Achias rothschildi:
and in Tephritidae, e.g. Pelmatopina sp.:
and I think there’s even at least one species in Drosophilidae that do this but I don’t recall the name.