{"id":1145,"date":"2014-11-27T10:11:56","date_gmt":"2014-11-27T10:11:56","guid":{"rendered":"http:\/\/tachinidae.org.uk\/blog\/?p=1145"},"modified":"2020-08-01T16:36:43","modified_gmt":"2020-08-01T16:36:43","slug":"linnaemya-picta-tessellans-rossia-confusion-features","status":"publish","type":"post","link":"https:\/\/tachinidae.org.uk\/blog\/linnaemya-picta-tessellans-rossia-confusion-features\/","title":{"rendered":"Linnaemya picta, tessellans & rossica confusion features"},"content":{"rendered":"

For many years Linnaemya picta<\/em> had been confused with rossica<\/em> because early workers (e.g. Fonseca) hadn’t tried using the European keys. Since the ‘discovery’ of picta<\/em> in Kent it has spread across southern England as far as Bedfordshire, Oxfordshire & Berkshire and so now we have another fairly common black-legged species to confuse with tessellans<\/em>. I have occasionally been confused myself by 2 couplets in the Linnaemya keys and so I have posted here some photos of the various species and illustrated the features that you need to look out for.<\/p>\n

Firstly, both picta<\/em> & tessellans<\/em> have dark hairs on the gena but picta<\/em> has bristles mixed in with them. The bristles should be fairly obvious because they arise from sockets, while the hairs go directly into the integument.<\/p>\n

Secondly, both picta<\/em> & rossica<\/em> have a scattering of small black bristlets on top of the head, behind the post-ocular row. But rossica is distinctive in having many more bristles in multiple rows and at least a few of them are as large as medium-sized post-ocular bristles. This feature is actually very easy to find but can cause confusion if you only have a picta and don’t know whether your bristles are big enough.<\/p>\n