RECORDS Syrphid (Hover) flies for ID

JRsbugs · #21 (**permalink**) 23-11-2009, 08:44 PM

Didea fasciata male, taken on 5th August 2009. First sighting since August 2007.

Diptera.info - Discussion Forum: Syrphid with red-tinged wings

Two confusing males which I have thought could be Syrphus ribesii but they look a lot like Epistrophe melanostoma too. Taken on 5th and 22nd August 2009.

Episyrphus balteatus, an unusual form on 5th August 2009. Male and female on Lilium on 15th July 2009. They are around at many times of the year including now and I have a lot of pics.

bonitin · #22 (**permalink**) 24-11-2009, 12:08 AM

Truly interesting thread with lots of potential!! Thanks!
So nice to have them all in one thread. This can be very helpful for all of us!

I'm very intrigued by the unusual form of Episyrphus balteatus, it doesn't really look like it, it has a strange body shape too, interesting..

Jason Green · #23 (**permalink**) 24-11-2009, 12:12 AM

Quote:

Originally Posted by bonitin

I'm very intrigued by the unusual form of Episyrphus balteatus, it doesn't really look like it, it has a strange body shape too, interesting..

To me, it looks like a dehydrated (...a fairly deflated look?) and late-season (...darker colours preserve internal heat) individual.

JRsbugs · #24 (**permalink**) 24-11-2009, 12:27 AM

Thanks bonitin..

There's two pics of Episyrphus balteatus on diptera.info which are described as "intersex", one looks much like my unusual one. It does look a little damaged but is not so dissimlar to this one...

Diptera.info - Photo Albums: Episyrphus balteatus (intersex) (1)

I'm trying to sort out my Eristalis.... I just realised I have another E. interrupta male

Some are not as easy as you might think.

Hopefully this thread will be useful to many.

Geoff F · #25 (**permalink**) 24-11-2009, 03:10 PM

Hello Janet,

I have started looking through your images on this thread and so have have considered the first 3 posts of photos.

From my rather limited knowledge of these species I would broadly agree with you so far.

Eupeodes latifasciatus is probably correct providing E. nitens can be ruled out. The yellow bands on your specimen may be a bit on the wavy side like E. nitens but are close to the tergite edges like E. latifasciatus so ideally I would like to see a bit more leg to be sure.

With your first Pipiza female, the yellow spots appear to be rather long and straight sided like P. luteitarsis although the antennae are quite long as P. noctiluca. Once again, more leg is required particularly the front tarsus.

With the Pipiza male, the yellow spots seem shorter and more rounded just like a typical P. noctiluca should be. Your Pipiza on Geranium could also be P. noctiluca.

Your Baccha elongata looks fine to me.

Cheilosia pagana males, with smaller antennae than females, are difficult to separate from C. bergenstammi although the latter should have a black ring on the tibia. So I'm not at all sure on this one.

The Cheilosia sp. female with a short rounded abdomen and part black femora with the remainder of the legs being orange does make me consider C. fraterna. The antennae are pale but are they sufficiently orange for this species?

Just my thoughts so far. I will add a few of my unidentifieds for suggestions.

Geoff F · #26 (**permalink**) 24-11-2009, 04:29 PM

It is amazing how it is possible to see things differently on a review of ID. One apparent Syrphus sp. which had totally eluded me became an obvious gavid Sphaerophoria probably S. scripta, but some females are difficult (flies I mean).

Well here are 3 flies which are currently causing me problems. I suspect they may well remain unidentified but someone else may see them differently.

With this Sphaerophoria male , I thought the wings seemed a touch long for S. scripta and the markings at the tip of the abdomen aren't typical for that species. I was considering S. interrupta instead but I'm not sure if the Scutellum is too yellow.

This late season specimen may be a Platycheirus and originally I was considering P. clypeatus, but the more I look at it the more doubts I have.

This was on April 30 and I had considered Cheilosia possibly C. bergenstammi but with it's head stuck in a buttercup, I just can't see enough to form a reasonable opinion.

So if anybody has any ideas, I will be grateful.

JRsbugs · #27 (**permalink**) 24-11-2009, 07:23 PM

Hi Geoff, thanks for looking at my pics and for the suggestions. I'm getting much the same problems as you with Platycheirus, I spend hours looking and changing names then remove the species name altogether! I really should have a book, but the only way I think for me to get a chance of ID on the difficult ones is to get the expert to look on diptera.info, he is very good on Platycheirus, all syrphids in fact even if he had a rare day off for which he was very apologetic.

Sphaerophoria I think are difficult without a specimen, but I don't know if a few good close up angles would make it possible. Mostly they end up being called S. scripta but we should be aware that it may not be correct.

I do have a pic of the Pipiza showing the front tarsi, but it's distant. They look to be banded from what I can see. Again these are notoriously difficult from pics, I wish I had a better lens last year but I'm making up for it this year.

I'll upload the pic anyway as well as a few Eristalis which I'm sure of, others I need to be more sure of.

JRsbugs · #28 (**permalink**) 24-11-2009, 07:48 PM

Same Pipiza sp. female on Clematis Juuli on 21st July 2008. (the pic has the wrong title but I put a note under it)

Eristalis arbustorum female and male. The female can have no orange marks on the abdomen but the outline is just visible on this one. The male typically has the shape as seen. This species has a 'pilose' face with no stripe or a barely visible glossy median line. The upper section (approx. 2/3) of the tibia on the middle leg is pale, with the upper section of the mid tarsi bright yellow. Arista (hairs on antennae) pilose (feathered).

Geoff F · #29 (**permalink**) 24-11-2009, 08:13 PM

As far as I can understand these species, it comes down to whether the tip of the fore leg tarsus is yellow or black.

I have been looking at your Cheilosia possibly scutellata photos and can't get anything certain here. C. scutellata females should have the classic two tone scutellum but males are all dark.

I think the antennae and thoracic/abdominal hair should be darkish, while your specimens are quite pale. The resemblance to C. bergenstammi here is making me consider C. urbana (dull orange antennae) but possibly the legs are too orange. But I'm really just guessing now; and with over 30 species of Cheilosia it needs a proper specialist to sort this out.

On a more encouraging tone, I have sorted through my hoverfly records and got 30 identifiable species over the past 2 years.

Tormentil's Sphaerophoria scripta males are very typical of the correct colouration and abdomen to wing length.

JRsbugs · #30 (**permalink**) 24-11-2009, 08:17 PM

Eristalis interrupta (not interruptus).

Female taken on 25th July 2009 on Ragwort (very popluar with insects!).

Male taken on 14th & 16th June 2009. These are the only pics I have and as far as I know the first. Female has been verified, male not but it has the correct features. Very similar to E. arbustorum but with a small 'dot' in place of the stigma (dark patch) on the wing edge. Features to look for are...

Mostly orange flagellum (the floppy bit of the antenna), black tarsi (feet). Another feature to check if in doubt is orange spines on the anteroventral surface of the hind tarsi. In flies the 'antero' part is the front part, and 'ventral' is underneath so it's the underneath bit of the front of the hind tarsi!

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