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 Tachinidae ex pupae, Oct.26, 2006
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| Dmitry Gavryushin |
Posted on 30-10-2006 08:53
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 Member Location: Posts: 3303 Joined: 17.10.05 |
So the case is closed I suppose  (it's very unlikely I'll see any Tachinidae until late March  ) |
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| Zeegers |
Posted on 30-10-2006 09:12
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Member Location: Posts: 18446 Joined: 21.07.04 |
And, to add to Chris, the reddish spot on thorax before scutellum are a typical 'jizz' for C. rasa. By the way, the headshot is from a male ! Unless I'm very mistaking. Theo |
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| Dmitry Gavryushin |
Posted on 30-10-2006 10:23
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Member Location: Posts: 3303 Joined: 17.10.05 |
Well Theo I thought I checked them all - maybe my examination wasn't too thorough - will look in the evening - I'm afraid it's too late for any manipulations though. |
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| ChrisR |
Posted on 30-10-2006 10:38
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 Administrator Location: Posts: 7699 Joined: 12.07.04 |
Yeah, the frons looks exceptionaly narrow for a female. From the Central European key (again assuming that it really does have a yellow basicosta and 1 anterodorsal on the mid tibia): bombylans: Frons 0.53 - 0.61x as wide as one eye in males, 0.63 - 0.71x in females rasa: Frons 0.42 - 0.50x as wide as one eye in males, 0.47 - 0.58x in females puberula: Frons 0.64 - 0.72x as wide as one eye in males, 0.72 - 0.87x in females But it is a very tricky measurement to get right first time - I have tried it with several experienced dipterists and it took a few goes to get the technique consistent. You really have to look down on the head perpendicularly from above. Then I usually use my zoom and a graticule to make the frons exacty 1 or 2 marks wide - then compare with the clearest eye - allowing for the drift in focus as you look for the widest point  Would be very interesting to know if it is really a female and it has measurements less than is normal for C.rasa.  Just another thought: they are freshly emerged so it might be worth waiting until they are dead and dry before measuring them. By that time the head may have changed shape a little. That's one important thing to remember - keys are always made from dead material, not from photos of living flies! |
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| pierred |
Posted on 30-10-2006 21:13
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 Member Location: Posts: 1413 Joined: 21.04.05 |
Chris, Could you explain why individuals coming from a single host are always of the same sex? Pierre Duhem |
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| ChrisR |
Posted on 31-10-2006 00:41
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Administrator Location: Posts: 7699 Joined: 12.07.04 |
No But I'd like to know if anyone else knows! Theo? I am not sure if it always happens either but every time I have seen reared material it has always been the same sex. |
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