Diptera.info :: Family forums :: Syrphidae
 Xanth. dives or pedissequum?
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| Guenter |
Posted on 25-07-2009 21:15
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Member Location: Dornbirn, Austria Posts: 278 Joined: 09.12.05 |
Hello, StN-Keys 2008 for Xanthogramma couplet 5 is as following: 5 Second basal cell of wing 90% or more covered in microtrichia; pale marks on tg.2 usually reaching their greatest length on the lateral margins of the tergite, so that there they extend closest to the posterior margin of the tergite (may only reach as close to the posterior margin as elsewhere on the tergite); pale marks on tg.3 expanded on the lateral margins of the tergite, so that there they occupy a greater part of the length of the tergite than elsewhere (or at least as great a length of the tergite as elsewhere); sternite 3 short-haired (1-4 pale marks on the thoracic pleura) ............................................................................................... pedissequum (Harris) (male) ----- 2nd basal cell of wing 25-90% bare of microtrichia; pale marks on tg.2 cut away postero-laterally, so that usually they are closest to the posterior margin of the tergite at some distance from its lateral margins; pale marks on tg.3 cut away antero-laterally, so that they occupy a greater part of the length of the tergite at some distance from its lateral margins (3-4 pale marks on the thoracic pleura) .......................... dives (Rondani) (male) In this male specimen the characters are as following: 1) Second basal cell of wing completely covered in microtrichia (nearly 100%) --> pedissequum 2) pale marks on tg.2 cut away postero-laterally --> dives 3) pale marks on tg.3 cut away antero-laterally --> dives 4) hairs on sternite 3 shorter and more adpressed than those on sternite 2 --> pedissequum? 5) 1 pale mark on the thoracic pleura on each side --> pedissequum So which species does the specimen belong to? Caught 3 weeks ago in Dornbirn/Austria Regards Günter Guenter attached the following image:  [116.71Kb] Edited by Guenter on 25-07-2009 21:23 Günter Schwendinger |
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| Guenter |
Posted on 25-07-2009 21:16
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Member Location: Dornbirn, Austria Posts: 278 Joined: 09.12.05 |
The wing
Guenter attached the following image:  [34.35Kb] Günter Schwendinger |
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| Lukasz Mielczarek |
Posted on 25-07-2009 22:49
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 Member Location: Poland, Krakow Posts: 498 Joined: 27.09.06 |
You must also include Xanthogramma stackelbergi Violovitsh 1975. It is very dificult group of species . At this time I have a problem with them |
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| Andre |
Posted on 26-07-2009 22:58
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 Member Location: Tilburg, the Netherlands Posts: 2111 Joined: 18.07.04 |
Comparing with dives/stackelbergi I saw a couple of weeks ago (from Serbia/Romania), and with what I assume as being pedissequum.... In my view at the moment pedissequum has quite clearly triangular spots on T2, like in this specimen. Whereas dives/stackelbergi show more oval rounded spots laterally to my opinion. So your specimen would to my opinion be pedissequum. PS: males of dives/stackelbergi cannot be identified to species level at this moment Edited by Andre on 26-07-2009 22:59 |
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| Guenter |
Posted on 29-07-2009 10:43
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Member Location: Dornbirn, Austria Posts: 278 Joined: 09.12.05 |
Thank you Lukasz and Andre for the comments. In my opinion the spots in my specimen are quite similar to the ones in the specimen determined by Dieter Doczkal as X. dives in this thread: http://www.dipter...d_id=21377 So I'm still not sure 
Günter Schwendinger |
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| Guenter |
Posted on 29-07-2009 10:48
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Member Location: Dornbirn, Austria Posts: 278 Joined: 09.12.05 |
By the way, is a black facial stripe only an intraspecific variation in Xanthogramma?
Günter Schwendinger |
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| Andre |
Posted on 29-07-2009 23:49
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Member Location: Tilburg, the Netherlands Posts: 2111 Joined: 18.07.04 |
Guenter wrote: By the way, is a black facial stripe only an intraspecific variation in Xanthogramma? Yes, it is. |
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| Guenter |
Posted on 03-08-2009 12:06
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Member Location: Dornbirn, Austria Posts: 278 Joined: 09.12.05 |
Thank you Andre
Günter Schwendinger |
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