I have two Robber flies from two days apart which appear to be the same from the pictures I have found, but to me look different.
The first one, sunning itself on a Calla lily, looks like the female in the same postion at the bottom of the page on the diptera.info site.
http://www.diptera.info/photogallery.php?album_id=3&rowstart=60
The second one, two days later, was having lunch. The side view of mine looks like the same fly as shown in the same position, top pic on the next link, also a female.
http://www.geller-grimm.de/genera09.htm
A back view, it looks brown where the first one looked greyish on the thorax, maybe it was the different light? They both match the pics of Tolmerus atricapillus.
The poor fly was having it's head held as it struggled, horror movie stuff!
Comparing my pics with those on the links I can find no differences other than the first one on the dipter.info site being a male,mine is female in both.
I think the first one looks darker because of the light as it was evening, and the camera does over-react to a light coloured background, darkening the subject.
I have never seen one of these before, they were both within 2 days of each other.
I will leave this open for a little longer, and unless anyone objects I will close it.
