Linnaemya picta was added to the British list after Howard Bentley got in touch with me with some dubious records for L.rossica, in Kent. L.rossica always occurs in upland areas and so a woodland in Kent just wasn’t a viable habitat. I contacted Theo Zeegers in Holland and he suggested that we check them against L.picta because that would be the most likely alternative … and it was. I then contacted Nigel Wyatt at the BMNH and asked him to check their Kent holdings of L.rossica (they had some collected by Fonseca in the 50’s) and he confirmed that they too were all L.picta – a problem solved!
Since Howard’s initial discovery Steve Downes & Ivan Perry have discovered Linnaemya picta in good numbers in Suffolk & Cambridgeshire (2011).
L.picta will key easily to rossica in the old Belshaw keys but can be distinguished easily:
1. Posterodorsal part of the head, behind the post-ocular row, with 2-8 long, stout bristles in addition to small black hairs mixed with the white hairs [palps almost as long as the length of the mentum] …… rossica Zimin
– Posterodorsal part of the head, behind the post-ocular row, with just a scattering of fine black hairs mixed with the white hairs [palps less than half of the length of the mentum] …… picta (Meigen)