Found beside the river in Lincolnshire, UK, about a week ago (20 Aug 2020 ish).
Initially I thought she was semi-claustral as her gaster is smaller than eg Lasius niger. I set her up in a tub n tube but she doesn't seem to be eating or drinking, or hunting, hasn't settled in and is still trying to escape. I realised last night she doesn't seem to have a post petiole so is unlikely to be what I initially thought (Myrmica).
If anyone could help that would be great thanks.
Size is 9mm. She looks black in some lights, though looks brown in these photos. Her head is heart shaped.
Edited by steelplant, August 27 2020 - 4:31 AM.