{"id":1066,"date":"2012-06-16T14:29:27","date_gmt":"2012-06-16T14:29:27","guid":{"rendered":"http:\/\/tachinidae.org.uk\/blog\/?p=1066"},"modified":"2020-08-01T16:39:06","modified_gmt":"2020-08-01T16:39:06","slug":"distinguishing-species-of-thelaira","status":"publish","type":"post","link":"https:\/\/tachinidae.org.uk\/blog\/distinguishing-species-of-thelaira\/","title":{"rendered":"Distinguishing species of Thelaira"},"content":{"rendered":"

In my experience a lot of people have trouble with this genus because the traditional features used in keys are quite variable. In particular it is difficult to separate the common Thelaira nigripes<\/em> from the rare solivaga<\/em>.<\/p>\n

All keys use the size of the outer-vertical bristles and the anterodorsal bristles on the middle tibia, which are a bit variable, and Belshaw (1993) uses the colour of the abdomen, which is one of the worst features to rely on – it is a confirmatory feature at best. This leads to a lot of Thelaira nigripes<\/em> being wrongly classified as Thelaira solivaga<\/em> – the 2 species are very similar but they can be distinguished if the correct features are used.<\/p>\n

Belshaw is a little ambiguous when he talks of the middle leg  only having “2 long bristles on its anterodorsal surface”. What constitutes “long”? All Thelaira<\/em> have both long and short bristles on the ad surface of the mid tibia but I prefer to ignore the smaller ones at the top and bottom of the tibia and focus on the rest, in the middle. Here are some photos of Thelaira nigripes<\/em> tibiae:<\/p>\n

\"\"<\/a>\"\"<\/a><\/p>\n

Here is a photo of a Thelaira solivaga<\/em> mid tibia:<\/p>\n

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Also, a very useful approach is to look at the male genitalia – here is a nice set of figures from an article I saw a while ago:<\/p>\n

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43<\/strong> – Thelaira leucozona<\/em> (Panzer, 1809); 44<\/strong> – Thelaira solivaga<\/em> (Harris, 1780); 45<\/strong> – Thelaira nigripes<\/em> (Fabricius, 1794); 46<\/strong> – Phenicellia haematodes<\/em> (Meigen, 1824) (not British).<\/p>\n

Pay particular attention to the segment just before the genitalia themselves and the way that the surstylus curves. The distinction between nigripes<\/em> and solivaga<\/em> is still very fine but in conjunction with the other features you should be able to make a more confident determination. Later I will add some closeup photos of the male genitalia.<\/p>\n","protected":false},"excerpt":{"rendered":"

In my experience a lot of people have trouble with this genus because the traditional features used in keys are quite variable. In particular it…<\/p>\n","protected":false},"author":1,"featured_media":1073,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[322],"tags":[],"class_list":["post-1066","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tutorials"],"_links":{"self":[{"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/posts\/1066","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/comments?post=1066"}],"version-history":[{"count":9,"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/posts\/1066\/revisions"}],"predecessor-version":[{"id":1364,"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/posts\/1066\/revisions\/1364"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/media\/1073"}],"wp:attachment":[{"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/media?parent=1066"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/categories?post=1066"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/tags?post=1066"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}