The fly it's eating is not the same species, nor the same suborder, it looks like an acalyptrate to me due to the lack of a complete transverse suture on its scutum. Remember that all flies are adults and do not grow, so this couldn't be an immature Coenosia. A Coenosia might eat a member of its own species, but it would be unlikely to encounter a maggot as it generally hunts flying insects, and I'd imagine it would find it difficult (not impossible) to eat something the size of another tiger fly.

For someone who is clueless about insects, they look a lot alike. Arlon

But I should have remembered that a young fly is known by the name of "maggot" and that the adults may grow a bit fatter, but never all-around larger.

BTW, this is a nice photo. I based some of my mistaken small fly ID on veins in the wings, also known as venation. Having wings and face clearly photographed aids greatly in ID of flies. You've certainly done that here!

I sure slipped up on the "eat their young" thing, but wings and thorax of the little guy do look like the big one. Sorry for providing bad info!

BTW, it is a tiger fly, is it not?

double post