Ants (superfamily Formicoidea)

I have been using the guide by Gary Skinner and Geoffrey Allen in the Naturalists' Handbooks series published by Pelagic Publishing, and this seems pretty good, though I have had some challenges using it. The plates and drawings were published in 1996 and although the inside cover says the text was published in 2015 this came as a surprise to me - the whole thing feels like it's from the 90s - I'd have been less surprised if it the 2015 had been a reprint date. I'm guessing it was originally published in 1996 and the text was revised to some extent in 2015 but not completely rewritten? In any case, dated or not, it has been sufficient for me to identify the majority of the ants I've examined - correctly I hope!

I've also now got the more substantial photographic guide to Ants of Britain and Europe by Lebas, Galkowski, Blatrix and Wegnez - this has a lot of really useful information lacking in the earlier guide and is well worth getting, but only seems to have keys for workers. Also it doesn't seem to deal with separating some of the most closely-related species from one another, for example the entire subgenus Chthonolasius is effectively lumped, the individual species within the group just listed so it doesn't tell you how to separate Lasius umbratus from other members of this subgenus.

Jet Ant Lasius fuliginosus

Yellow Meadow Ant Lasius flavus

Lasius mixtus

Lasius umbratus