That is one seriously long proboscis. I'm not entirely sure what kind of fly this is. Its ridiculous eyes make me want to say Syrphidae, but overall it has the appearance of an asilid. My very, very loose interpretation of my key suggests Mydidae as a possibility, but without a specimen in hand to count tarsal pads and the like, I'm not sure.

Update: ap2il suggests Empididae, and it sure looks like one.