Found this pretty big feller on the hood of my car this evening. This is by far the biggest mayfly I have ever seen around these parts. Its a camera picture, so excuse the quality. I put a dime next to it for a size reference. Its quite a pretty bug Any guesses what it is? I would guess march brown, but I don't have my hatch guide to western streams book handy as it was stolen by my 2 year old daughter so she could flip through pages saying "BUGS! FLIES!"