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This one is giving me a difficult time. I have collected the specimen, but keep taking the wrong directions in trying to name it.

Can someone give me a clue about a genus?

Thanks in advance

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Pelatachina tibialis

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Where is it going in the key? Does the humeral callus have bristles in a forward-pointing triangle, like Nemorilla? Could it be something like Oswaldia or Blondelia? Would be easier if we could see a dorsal view too :)

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Hi Erikas and Chris.

The first thing where it goes wrong is in the question about the setae on the humeral callas. Determining if the setae are in a straight line seems to be rather difficult for me :(

In the accompanying photo, the setae on the callus should be on a straight line. In my opinion, it depends on the angle with which you look.

Pelatachina tibialis is correct, after overcoming my doubts on the humeral callus question, the key goes straight on to that species.

Thanks Erikas and Chris, mystery solved

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Glad you got it sorted anyway - it looked a bit too black/white in the photo but I rarely see them alive and sitting on leaves! :D

The humeral callus bristles do confuse some people ... I just see the triangle (or not) immediately but others do struggle. It is possibly because 95% of the flies you will key will not have the triangle so most of the time you are looking at negatives, which is never very confidence-inspiring! There are only a few genera that are positives on that test - like Nemorilla (getting rarer to find these days), Myxexoristops (incredibly rare), Phebellia (rare) and Allophorocera (also uncommon).

See if you can see the triangle on my tutorial page here: http://tachinidae...age_id=791. Basically the triangle should be roughly equilateral and forward-pointing, and be comprised of the 3 strongest and most posterior bristles on the humeral callus.

Let me know how you get on with that :)

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PS: I think I can see what you mean - the middle bristle is pushed forward a bit but it isn't really equilateral because the middle bristle is offset to one side and it isn't pushed forward by >2x the basal width (a test used in the Neotropical key).

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Yes Chris, thats exactly the problem i had. Of course it is definitely not equilateral.

I have made a note at couple 64 in my key and added a reference to your tutorial, which absolutely clarifies the problem for me.

Thanks again.