Fly coincidence

goosey · #1 (**permalink**) 08-06-2011, 07:53 AM

Yesterday I was in the NP having a wander and I saw this large fly, about 2cm long it was on garlic mustard. Then later on I saw what could be the same type in our garden, the only difference I think is the apex of the tail, I take it one is a male and one is a female, but I don't know which is which or for that matter what type of fly it is.

1.

2.

black · #2 (**permalink**) 08-06-2011, 10:54 AM

Probably one of the Robber Flies Asilidae sp. it looks mean and hanging around ready to attack.

Pudding4brains · #3 (**permalink**) 08-06-2011, 06:29 PM

Howdy,

I'd say you're probably right in the coincidence dept.

IMHO (humble being the operative word there - dunno flies, really) this might very well be female & male (in that order) of Neoitamus cyanurus.

Cheers, Arp

goosey · #4 (**permalink**) 08-06-2011, 06:43 PM

Thanks Black and Arp for sorting me out

.

paul m · #5 (**permalink**) 09-06-2011, 10:22 AM

They're stronger than the average fly!
This gives me an opportunity to revive this old post - wondering if anyone has any further ideas.

Pudding4brains · #6 (**permalink**) 09-06-2011, 03:38 PM

Woah!

Here is another one from Greece, quite like yours (same bands on legs and all).

I'm trying a cheap trick here

Flies in the genus Promachus are know to be phat buggers. So I looked up in what subfamily these are sorted: Apocleinae.

Next step is to list the Apocleinae from the Greek mainland (source, FE (06-2011)):

Philodicus ponticus (Bigot 1880) - images @BOLD
Polyphonius theodori Hradsky & Huttinger 1992 - images ??
Promachus leoninus Loew 1848 - images: insorg

From that I'd say it's not the Promachus, nor the Philodicus but allas there are no images to be found for Polyphonius theodori little surprising seeing the date it was first described (1992). Then again, there may be sexual dimorfism in the hairs/colours and/or FE might be missing some and/or there may be other subfamilies yet with giants. I'll ask a german Robber Fly specialist, he might have some ideas.

Cheers, Arp

Pudding4brains · #7 (**permalink**) 09-06-2011, 09:42 PM

Well, the verdict is in

(and I was way off above

)

It should be a Stenopogon sp.

According to FE some 10 (sub)species or so in Greece.

Had a quick look around and of all the thirty some topics on diptera.info that (presumably) have a Stenopogon in them only two or three did get a name to species. All the others linger at "sp." or unanswered even, and that's including topic where there is excellent close ups of the externals of the genitalia at the end of the abdomen.

Presumably there is no recent revision of the genus, which is apparently complicating things even for those with a keen eye for Asilids.

Cheers, Arp

paul m · #8 (**permalink**) 10-06-2011, 04:40 PM

Wow, what detective work - at high speed too! Thanks - I've just got back but I'll be off again for the weekend so shall contemplate all this information over the weekend!

JRsbugs · #9 (**permalink**) 12-06-2011, 01:45 PM

Hello!

You might be correct with your naming of the Asilidae goosey, but there's another species which is very similar. If you don't have that species you might be safe in calling it Neoitamus cyanurus, that is if you don't have another one similar! Check out mine on diptera.info, I've seen this for three years now and the other is quite rare here.

Diptera.info - Discussion Forum: Asilid Neoitamus cyanurus?

Arp, the main problem with not getting to species with many of these is that a specimen is needed as you will see from the expert who posted on my thread. Have you seen this site..

Asilidae Homepage ( Insecta : Diptera ) - information on robber flies

Janet

Pudding4brains · #10 (**permalink**) 12-06-2011, 06:33 PM

Hi All,

Like I said, I don't know flies - not at all - so I'm not going to argue a case here. All I can say is that on waarneming.nl there has only been a single "reliable" observation of Neoitamus cothurnatus, unsurprisingly in Limburg (southern most part sticking into Germany and Belgium, which is something of an "exotic species" outpost

). ID as Neoitamus cyanurus is actually never even "discussed", so I'm assuming it's not really an issue, especially not in Noord-Holland.

Of course, all the Dipterists there might be mistaken. There are some knowledgeable folk there, but I'm not sure any specialize in Robber Flies.

As far as any discussion on these goes (on waarneming.nl), the two I've seen on the forum treated one Belgian specimen and one from Switzerland. With these, the following characters were discussed/used for ID:

Metatarsus all black (cya.) or with some yellow/red in it (cot.).
Brushes on tibia 1&2 all black (cya.) or some/most brushes yellow (cot.).
Only ab.segs. 1-5 "dusted" (cya.) or 1-6 dusted (cot.).
Some bump on the head (beyond me)
External shape of genitalia

Going by these characters and comparing to images of cot. these seem recognizable and the animals of Goosey would both fit for cyanurus. That said, when someone of the likes of Danny Wolff says it can't be done, then that's it (and the characters above are probably not reliable enough).

So I should probably ask the dutch folk how responsible all their IDs are

(will do that next).

All said, I would still assume it to be extremely probable that the ID is correct - even if I never suggested that it even was a proper ID, but I'll get back with an answer from the dutch Fly-Folk

Cheers, Arp

Pudding4brains · #11 (**permalink**) 12-06-2011, 07:51 PM

Quote:

Originally Posted by Pudding4brains

(will do that next).

Well, the first answer is in

It would seem that socius is known only from the southern parts of Limburg and that cothurnatus is extremely rare or even thought to be extinct in NL. Admittedly a tad iffy as ID criterium, but it explains the relative ease most people display in IDing these for the Netherlands.

Cheers, Arp

Pudding4brains · #12 (**permalink**) 13-06-2011, 12:28 PM

Hi all,

I'm not going to do a full translation, but the Belgian and Dutch guys on waarneming.nl seem to agree that the characters as mentioned should be valid (or put differently: it's what we have and should rely on unless other/more research is done).

All animals mentioned here (by Goosey and Janet) should be cyanurus.

I'll double check with Danny and ask why he wasn't sure, respectively which characters in his experience are iffy.

Cheers, Arp

JRsbugs · #13 (**permalink**) 16-06-2011, 10:42 PM

Hi Arp,

I didn't get an email notification (seems I didn't select to get one but I think I did!) so it's a good job I looked in! You've been doing some great research there, I'm interested to see what Danny has to say.

I dropped in to check on those Panorpa with two cells filled with black, I got a female today which looks well marked with two big black cells filled. I'll get them posted up soon..