Found this louse fly on a barred owl that was dead by the side of the road. I used the Manual of Nearctic Diptera to identify it to the genus Icosta. This was mostly by using the wingveins and can be done from these pictures. From what I could find, it seems that this may be Icosta americana since it was found on an owl, but there is at least one other Icosta that is found on owls and I couldn't find any recent keys to get this to species. Still, I was very excited to find one of these.