Thread subject: Diptera.info :: Phaonia (?) #3: P. pallida?

Posted by Juergen Peters on 24-08-2006 17:18
#1

Hello!

On Aconitum in our garden on August-19. Ist it Phaonia pallida or some other genus? Thanks!

Posted by Juergen Peters on 24-08-2006 17:18
#2

Another picture of the same fly.

Posted by Susan R Walter on 24-08-2006 19:54
#3

Venation, general appearance and thoracic bristle arrangement look like http://www.dipter...post_12609 , identified by Tony as P pallida.

Posted by Juergen Peters on 24-08-2006 20:51
#4

Hello, Susan!

Susan R Walter wrote:
Venation, general appearance and thoracic bristle arrangement look like http://www.dipter...post_12609 , identified by Tony as P pallida.


Thanks a lot!

Posted by Xespok on 24-08-2006 21:56
#5

In the Hungarian series on the identification of Diptera, there is a remark, that there are three very similar species to this, one is Phaonia pallida, and there are two other very pale Anthomyiids.

I observed some very similar flies. Could this be the male of the same species?

Posted by Juergen Peters on 25-08-2006 00:07
#6

Hello, Xespok!

Xespok wrote:
and there are two other very pale Anthomyiids.


I have read that Pegomyia silacea (Anthomyiidae) is also this pale.

Posted by Susan R Walter on 25-08-2006 13:55
#7

I've looked at a number of images and it seems to me that the Phaonia pallida candidates have 4 post-sutural dorsocentrals, and the Pegomyia's have 3. This might be a dangerous over generalisation though. I expect Tony can tell us.

If my observation is accurate, then Xespok's is right that his male fly is also P pallida

Also, the fly above has that rather overstuffed abdominal look that some Muscids have. There is supposed to be something about the line of the back of the head that helps you distinguish between Muscids and Anthos, and I can never remember how it goes - one is supposed to be flatter, less rounded than the other I think. There are also differences in the leg bristles between Muscids and Anthos, but we can't see enough of these to help I think.

Posted by Susan R Walter on 25-08-2006 23:31
#8

Sorry Crex. My understanding of postsutural dorsocentral (which won't be the exact scientific definition, but hopefully helpful) is that calyptrate flies have a suture ie the groove or indentation that runs across top of the thorax from 'shoulder' to 'shoulder'. Bristles run in rows down the length of the thorax and if you count the number in one of the centrally placed rows, between the suture and the scutellum, it can be an important clue to genera, and sometimes species.

Posted by crex on 26-08-2006 08:26
#9

Thank you Susan for explaining it! :)

Posted by Xespok on 26-08-2006 09:18
#10

Susan, thx for your input.

Posted by Xespok on 26-08-2006 09:21
#11

In addition it is maybe interesting to mention that this species seems to prefer shady places unlike most of the other Phaonia-like species. This means that I ussually observed this fly in the undergrowth of the forest, and the fly often perched on the underside of leaves, which I never saw for similar flies.