Warning... this is not a beneficial insect! I was just so shocked to see this sight... but if you don't like seeing the ugly side of nature, don't look further!
This robber fly, possibly Efferia, has captured a horsefly! Man, they must be quick because the horsefly sure is!!
Now, let me just say that I don't really like seeing either one of these hanging around! The robber flies capture various bees, wasps and other flying insects, paralyze them and drink the fluids from their prey. The horseflies race around here harassing us and the animals! They will bite and take a chuck of meat out of you before you know what hit!
For whatever reason, the horseflies and deerflies have been bad this year. But now that I think about it, I've been seeing more robber flies than usual this year too.
Ooops! I posted the wrong picture.. this one is a little bit clearer:
