Many thanks Tony. Interestingly the site (https://www.naturespot.org.uk/wild-place/spearwort-fields) also has a couple of other mainly coastal species including Nemotelus uliginosus. I'll submit the record via NatureSpot (iRecord).
Hi All, Fell upon this as I was revamping my Flickr site and tidying up the Sarcophagidae section https://www.flickr.com/photos/63075200@N07/collections/72157717896352376/ and I'm pretty sure it is not germanica because I can just make out dark spots on the tergites. I think it might be M. punctatum but Pterella can look so similar and you can't check for vibrissae in these views. But scrutinise my new folders and see if you can use the body markings to decide which it might be (that's the reason I include so many photos). I've had germari areound leachella nests in Sussex but you can get so many aculeates using a common patch of ground it can be really confusing.
Hi Becca,
Can't really help with your images. However, I wondered why you are relying on this feature? There are a number of differences between the two Delia species you mention and B. fugax. The most obvious difference is the more or less complete, evenly spaced row of c.20 erect PV setae on the hind tibiae in both Delia species (though not present in many other Delia species). The male genitalia are also very different between the genera and can be easily examined without dissection on fresh specimens by leavering out the surstyli using a micropin. Of course you may well already be aware of these feature and have a reason to use the prealar bristle character. Obviously neither of the characters I've mentioned is of any help if you're working on females.
Sam
The rather blunt end to the abdomen and the absence of post-spiracular bristles excludes Aedes and Ochlerotatus. Your thorax picture shows the prespiracular bristles very clearly, and combined with the banded tarsi indicate Culiseta. The dark spots on the wings combined with the subapical ring on the femora take us to annulata/subochracea. Finally the clearly marked pale basal rings on the tergites suggest annulata.
Doh! Inexplicable user error. I noted the post-spiracular bristles weren't present then for some unknown reason went off down the other side of the key.
Thanks for the correction and explanation Tony. When you say 'suggest' does that mean the images don't give you enough confidence in that final choice for a record?
That's nought out of two for me keying mosquitoes so far but I'll keep trying. I'm using the RES key IX, pt2, 1950. Is there anything more recent?
I'm a bit wary of IDing anything with certainty from a photo, but in this case, I'd say the ID is almost certainly OK - partly a function of it being a very common, widespread and distinctive species. Having said that, there have been quite a few additions to the British list in recent years, so it's as well not to take anything for granted.
Cranston, Ramsdale, Snow and White 1987 Adults larvae and pupae of British mosquitoes (FBA Scientific Publication no. 48) - See Pemberley Books (£13) - covers most of the species.
There is an RES handbook on the Phoridae, but it excludes the genus Megaselia. Since this is much the largest genus in the family, and most of the Phoridae I ever come across seem to belong to it, I haven't found this handbook very useful! I believe that there have also been many additions to the family since the handbook was published in 1983. If anyone knows of anything more comprehensive and up-to-date I too would be interested to hear about it.
Slightly damaged copies of the handbook are available from the Ent Soc at a bargain price of £3.00 - See https://www.royensoc.co.uk/publications/handbooks/scuttle-flies-diptera-phoridae-except-megaselia
The large isolated bristles on the tibiae suggest that this is not Megaselia, so if you have the specimen, it should be fairly easy to key. From just a photo, I'd hesitate to place it in a genus!
Once you get hooked on the family, the Megaselia handbook (males only) is available to download -
see https://www.royensoc.co.uk/sites/default/files/Archive%202/Vol10_Part08_Disney.pdf
Great pictures, Colin. These are so difficult from photos though, however good they are. Look again at the epandrium - your last two pictures seem to show setae which may be on the epandrium - at the angles they're taken at it's difficult to tell just where they arise. I think this is probably E. minuta, but I'm not certain about it. Michael would have known, of course, but sadly he's no longer with us.
No, these are Ochlerotatus (formerly Aedes) - note that the pale rings include the base and the end of each joint of the tarsus (in most species, it's just the base that is pale), and that the thorax is evenly ginger with two narrow, pale lines. This combination identifies them as Oc. caspius - most often found in coastal sites, but occasionally from inland localities. Please do submit your record to the Mosquitoes Recording Scheme.