#carnidae

oh yeah, that makes sense. dance flies (Empididae) can get pretty crazy. as for why, i think you tend see a lot of interesting morphological variations in arthropod groups that are already highly visually oriented. see for example peacock spiders or stomatopods. it’s usually sex related. i am curious about which species you’re referring to though, since i’ve seen plenty of empidids with big bulbous thoraxes, but i’m not familiar with any that are more elaborately modified than that. i am glad you brought up the ones with the inflatable abdomens, Rhamphomyia longicauda, because i love them

source. that’s the female regular style on the left and inflated on the right, one of the rarer cases where it’s the female of the species who’s the one with the funky features. in this case it’s because she’s trying to look as fecund as possible to increase the chances of being chosen by a male, who as part of the mating ritual will come bearing a prey item for her to consume. so the abdominal modifications are an attempt to get a free meal.

SO! as to your other question about the weirdest flies, man we could be here all day. in order to not have this post be 100 pages long, i’ll focus on “ flies that just don’t look like flies“ which to me largely brings to mind some of the more highly modified wingless flies. 

the first thing i think of is the family phoridae, which you’re probably familiar as the “zombie ant flies” or something like that since there were a bunch of articles about them a few years back. they’re a really diverse family, some species of which will lay their eggs on adult ants and the larvae will develop inside the ant’s body and pop out of the head when they’re developed. other species in the family are inquilines (nest parasites) of ant colonies rather than literal parasitoids of the ants like the “zombie” ones. here are some examples of what adult females can look like in some inquiline phorid species:

source, which is a paper describing the world’s smallest known adult fly, also a phorid

and here’s some species in the same family that are social parasites of termites (subfamily Termitoxeniinae):

source

of course there’s bat flies (family Nycteribiidae):

source

and sheep and deer keds (family Hippoboscidae):

source

and bee lice (family Braulidae):

source 1, source 2

and hairy hobgoblin flies (family Mormotomyiidae):

source

and some wingless crane flies in the genus Chionea (family Limoniidae):

source

and the bird parasite Carnus hemapterus (family Carnidae):

source

the above is by no means an exhaustive list of cool wingless flies, but it’s a good start. in the interest of fairness, here are a few cool flies with wings:

beetle flies (family Celyphidae):

source, also see my other post about them (the wings are hidden under the enlarged scutellum)

antlered flies (family Tephritidae, genus Phytalmia):

source unknown, also fuck pinterest

Anaeropsis guttipennis (family Micropezidae):

source is a photo i just took from an actual book since the only photo i can find online isn’t very good, those horns on it’s head are actually forward-facing eyestalks, as opposed to the usual lateral-facing eyestalks of other stalk-eyed flies (see below).

and now tumblr won’t allow me to add any more images to this post, which is reasonable, so check out my post on the various families of stalk-eyed flies