Gallery Links
Users Online
· Guests Online: 9

· Members Online: 0

· Total Members: 4,821
· Newest Member: igorotrebiev
Forum Threads
Theme Switcher
Switch to:
Last Seen Users
· weia00:44:20
· zdanko01:05:30
· Juergen Peters01:32:08
· smol01:55:10
· Mario Renden01:57:29
· Marion Fried...02:41:25
· ESant03:13:46
· Morten A Mjelde03:18:02
· rafael_carbo...03:20:34
· Christian Sc...03:29:00
Latest Photo Additions
View Thread
Diptera.info :: Family forums :: Syrphidae
Who is here? 1 guest(s)
 Print Thread
sirphidae
gordo
#1 Print Post
Posted on 24-11-2004 15:06
Member

Location: 06 FRANCE
Posts: 32
Joined: 27.10.04

hello,
I think this sirphidae is Cheilosa pictipennis, can you confirm my idea.
I see it on september.

www.diptera.info/forim/7-0126-1.jpg
CF
 
http://site.voila.fr/fauneflore06/pages/insecte/insecte.htm
Menno Reemer
#2 Print Post
Posted on 24-11-2004 15:26
Member

Location:
Posts: 343
Joined: 10.06.04

This is a female of Scaeva selenitica without the characteristic white abdominal markings. This abberation is often called var. unicolor, and it occurs in females in which the ovaries have not developed properly (possibly because of certain parasites).
The specimen is recognizable as a Scaeva species by the swollen frons and the S-curved wing vein r4+5. Cheilosia species do not usually have a yellow scutellum and face.
 
Paul Beuk
#3 Print Post
Posted on 24-11-2004 15:38
User Avatar

Super Administrator

Location: Netherlands
Posts: 19087
Joined: 11.05.04

I agree with Menno that it appears to be selenitica, but officially the form name unicolor is described for S. pyrastri and treated as synonym for that species.

Females with ovaries have been described for many more species and no doubt the phenomenon will occur in selenitica as well. In some of those species these 'females' are considered to be intersexes because they have intermediate characters between males and females and no developed genital structures. The intermediacy is especially clear in species of Platycheirus and Pyrophaena. In other species it usually appears as if the frons is narrower than in ordinary females.
In your specimen the frons does not really seems to be narrower, and since vague markings are visible (though much darker than normal) I am not yet convinced that this is a true 'unicolor'-like specimen.

For 'unicolor's also see images linked on http://www.bioima...R38418.HTM.
Paul

- - - -

Paul Beuk on https://diptera.info
 
diptera.info
Steve Crellin
#4 Print Post
Posted on 24-11-2004 16:31
Member

Location: Isle of Man
Posts: 41
Joined: 01.09.04

I don't doubt that the i.d of S. selentica is correct, baring in mind who has provided it, but what is it about this specimen that says "selentica" as opposed to "pyrastri"?

Generally, I would be relying on the differences in the abdominal markings between the two species, but in the case of this specimen these markings are not really available. Its always useful to know of other characters to use.
Edited by Steve Crellin on 24-11-2004 16:33
Steve Crellin
steve_crellin1@hotmail.co.uk
Isle of Man
 
Menno Reemer
#5 Print Post
Posted on 24-11-2004 16:49
Member

Location:
Posts: 343
Joined: 10.06.04

Oops, I accidentily wrote 'selenitica', but of course I meant pyrastri! Sorry for this mistake. There are two old papers by Van Doesburg which deal with this 'var. unicolor' , and he found several specimens of this abberation with incompletely developed ovaries. I do not have the references of these papers here, but I will let you know later.
 
Paul Beuk
#6 Print Post
Posted on 24-11-2004 21:38
User Avatar

Super Administrator

Location: Netherlands
Posts: 19087
Joined: 11.05.04

The references:

Doesburg Sr., P.H. van, 1964. Bijdrage tot de kennis van het melanisme bij Syrphiden. ? Entomologische Berichten, Amsterdam 24(6): 117-118.
Doesburg Sr., P.H. van, 1970. Female Syrphid flies without ovarium. ? Entomologische Berichten, Amsterdam 30(8): 157-158.

And about the identity: I was serious about the species more reminding me of S. selenitica than of S. pyrastri, especially the shape of the (very indistinct) markings. I do not have all the details on other characters here, but if someone has the decider why it cannot be S. selenitica, I would be happy to hear.
Paul

- - - -

Paul Beuk on https://diptera.info
 
diptera.info
Gerard Pennards
#7 Print Post
Posted on 04-12-2004 12:37
User Avatar

Member

Location: Amersfoort
Posts: 1914
Joined: 07.06.04

In general, if you find a specimen of Scaeva like this, there are other differences on which you can distinguish S. pyrastri from S. selenitica.
Pyrastri has on its sternites bigger, square dark markings, which are broader than high.
With S. selenitica, these markings are more rounded, and these are higher than broad.
Furthermore, selenitica usually has a black ring on the hind tibia, which is absent in pyrastri!

Greetings
Greetings,
Gerard Pennards
 
Jump to Forum:
Similar Threads
Thread Forum Replies Last Post
Sirphidae larvae 1 Syrphidae 3 11-02-2014 19:32
Sirphidae larvae? 4 Syrphidae 1 09-02-2014 16:12
Sirphidae larvae 3 Syrphidae 1 09-02-2014 16:11
Sirphidae larvae 2 Syrphidae 1 09-02-2014 16:11
Date and time
28 January 2023 01:52
Login
Username

Password



Not a member yet?
Click here to register.

Forgotten your password?
Request a new one here.
Temporary email?
Due to fact this site has functionality making use of your email address, any registration using a temporary email address will be rejected.

Paul
Donate
Please, help to make
Diptera.info
possible and enable
further improvements!
Latest Articles
Syrph the Net
Those who want to have access to the Syrph the Net database need to sign the
License Agreement -
Click to Download


Public files of Syrph the Net can be downloaded HERE

Last updated: 25.08.2011
Shoutbox
You must login to post a message.

27.12.22 21:10
Thanks, Jan Willem! Much appreciated. Grin

19.12.22 11:33
Thanks Paul for your work on keeping this forum available! Just made a donation via PayPal.

09.10.22 17:07
Yes, dipterologists from far abroad, please buy your copy at veldshop. Stamps will be expensive, but he, the book is unreasonably cheap Smile

07.10.22 11:55
Can any1 help out with a pdf copy of 1941 Hammer. Vidensk. Meddel. Dansk Naturhist. Foren. 105; thank you

05.10.22 19:59
Found! https://www.veldsh
op.nl

05.10.22 19:53
@zeegers, your book seems difficult to get from Spain, is there another way?

08.09.22 09:29
Ladies and gentlemen https://jeugdbonds
uitgeverij.nl/prod
uct/families-of-fl
ies-with-three-pul
villi/

26.08.22 15:06
Lis - This is vol.11 (eleven) and is 346 pages. Sorry, don't have a copy.

15.08.22 14:22
Hello, can any1 help out with a copy of Catalogue of Palaearctic Diptera II: Scathophagidae-Hyp
odennatidae? or at least how many pages it is? thx

19.06.22 07:42
I can not post an image - I do all right - dont know what to do! Gunther

Render time: 1.60 seconds | 173,515,747 unique visits