Thread subject: Diptera.info :: Is this a Helina species?

Posted by Gateside on 29-06-2018 13:01
#14

Hi John and Nini.

It is good to be sceptical!
I have used the Muscidae key for the UK, by ECM D'Assis Fonseca.
Therefore my reasoning is based on this key, which may not be the same as your key.

It does not matter that I cannot see the prosternum. The apical section of the discal vein is longer than the previous section, so not P. lardarius. The lower squama is not whitish, either. As a confirming feature, though not in the key, the venation is wrong anyway.
Cannot tell if cubital vein is definitely bare or not. Also front tibia not in focus. So have to check each of the 3 remaining possible species.
Eyes are not bare and the mid tibia has posteroventral bristles. Therefore not P. steini
Eyes densely hairy, and mid tibia with pv bristles. Lower squama conspicuously yellow. P. hirticrus.
Finally, it is not P. albolineatus, because although the eyes are densely hairy, there is no conspicuous broad white dusted median stripe. (see images elsewhere to check that feature, and the appearance of the entire fly)

I am therefore content that it can only be P. hirticrus

Regards
Nigel