Notes on some of the species seen in July (and June)
Some observations from the photographs taken over these two months include:
It would appear that most, if not all of the Megachile bees seen are the Patchwork Leafcutter Bee (Megachile centuncularis).
Robber-flies and Conopids
There are at least five Robber-fly (Asilidae) species (and possibly more) seen. It was only late in July I came across a paper on the differentiation of the Machimus species (Smart MJ “Identification of the females of the smaller British Machimus sensu lato (Diptera, Asilidae) with a note on the morphology of the ventral and abdominal thoracic plates” Dipterists Digest 2005 12, pages 61-68) and having read through it I believe that I have photographs of both M.atricapillus and M.cingulatus. These species have banded fibia and the latter has a lot of white hairs coming out of the frons (=face) whereas M.atricapillus only has a few, if any.
From the photographs it is certain that there are three other species noted in the pre-July 20th text grouped together under the generic name of Dioctria. One has thick black hind thighs and bands of golden hairs on the abdomen and is actually from a separate sub-family of the Asilidiae to the other two species. This one is from the Laphrinae and is called Choerades marginatus. The two actual Dioctria species can be separated on leg colouration and are both common species, one being D.rufipes (the Common Red-Legged Robber-fly although the legs in question are actually orange rather than red!) and the other species is D.baumaueri (aka D.hyalipennis in the main reference source online).
Another paper by PG Sutton “The Larger Brachycera and Conopidae of Bushy Park”, Middlesex, Bull.Amat.Ent.Soc 65 (464) 10-17 lists the species likely to be seen in the local area, Bushy Park is only a few miles away and all the species of Robber-fly mentioned above (along with the Horse-fly, Snipe-flies and Conopid flies recorded in the main text) have been recorded from there which is a good indication my identifications are correct! The only one not recorded was the Myopa conopid fly and I am pretty sure this identification is correct having checked several times and using several sources.
Tree Snipe-fly (Chrysopilus laetus)
There is some debate as to if this is actually two species C.laetus and C.luteolus differentiated by the thickness of the third antennal segment but only the former appears to be now listed for the UK.