An old image that looks like female Helophilus hybridus.
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Dark hairs on tip of tergite 5 I think which would agree with hybridus. The dusting on the frons should also extend up either side of the ocellar triangle, but can't quite see from this pic.
Jamie from Briantspuddle
Roger, I think you can see the yellow as it extends up on to that central part of the frons above the antennal insertion that I can't find a name for. This is clearly yellow in al my trivittatus pics I've zoomed in on - much yellower than the dusted sides of the face below the antennae in fact.
And also plate 12 in Stubbs & Falk - look carefully and you can just see it in the illustration compared with what has been shown as grey in helophilus - which the individual in this photo does have.
Sorry, mistyped last sentence watching Mrs Biggs.....should have read :..as grey in hybridus..
The facial stripe is not visible at all in this picture, as Roger says.
I do think it is probably hybridus myself (from the pattern around the ocellar triangle partly), but I also think there is a danger in contradicting a true expert on the basis of a few photos you have, when they have goodness knows how many actual specimens! I just had a look at some of my specimens, and that pattern on the frons does vary on hybridus and trivittatus, whereas the facial stripe (below the antennae and so not visible here) is a consistent feature.
My Flickr photos...
I think I've muddied the waters here by suggesting the colour around the antennal insertion is part of the facial stripe. Sorry! I have tended to look on it that way as, like Jamie, my personal observations have been that this is pale brown in H. trivittatus, or at least not as dark as the above specimen. But that is only based on a couple of dozen individuals and I realise there could be outliers I haven't seen.
If Roger says this can't be done to species with certainty then I'm happy to accept that.
Although that said, if I had the specimen in a pot I'd be willing to lay £50 against all comers that it was H. hybridus. There are two other things not so far mentioned that also make me lean towards hybridus: The shape of the spots on T4 is outside what I have seen for H. trivittatus, a fairly weak observation I admit. And the spots on T3 have a broader connection to the front margin in H. trivittatus, often hard to see as the spots can be partially dark in that area. Neither of which proves anything, other than that I might have avoided an expensive way to learn! :-)
It's all good discussion and makes good sense. I do think that a lot of people's idea of trivittatus is based around seeing males, though, and the same for hybridus. The females of both can be quite similar, though, especially in their shape and size, and quite different to the males. The female trivittatus shown here...
...is not very different at all to the fly above, for example.
Similarity is clearly in the eye of the beholder! :)
I'd consider that image a classic female trivittatus clearly illustrating some of the features we have discussed: The spots on T4 are stronger with a much more forward curved shaped (though not as exaggerated as the male). The spots on T3 show a broader attachment to the front edge (which is easily seen as they are fully coloured). And the antennal insertion point is pale brown.
Here is one I consider more difficult as the spots on T3 are partially dark. But if you look closely through the left wing you can see a dark grey area forming the same broad attachment as Steven Falk's image. (The spots on T4 are still classic female trivittatus.)
I take your point that males are much more common and probably skew our feel for the jizz of the species as a whole. Equally, I accept Roger's view that even in sum the features of this specimen are not outside the range of trivittatus, he has seen rather more than I have!
I guess it comes down to probabilities versus certainties and we want certainties for records. An interesting and enjoyable discussion though.
Agreed...interesting discussion. This has been an incredible year for both, especially hybridus, which has rivalled pendulus on some of my local sites.
I always look at the division of black/yellow at the front of the ocellar triangle...clear division in trivittatus and blurry in hybridus. Usually works, if face stripe is not visible.
I must admit, the dusting around the ocellar triangle is not something I normally look at. I will do in future though, thanks for the tip.
H. trivittatus has had an excellent year in Leicestershire, but nowhere near pendulus abundance; hybridus seems to be about in its normal low numbers (the occasional male).
(This image was from 2003 by the way.)
Ophrys, I don't think you could be more wrong: the whole point of forums like this is to challenge and add to the books and the current consensus, whether based on specimens or field/photo observation. If birders had stuck to identifying only museum specimens we'd still only be able to tell some species apart on the length of their hind claws. New bird field characters are being noticed and discussed the whole time, and I don't see why insects should be any different.
In this case I think I've noticed a field character for trivittatus, from field observations and photos on the web, which doesn't feature in the texts or keys, but, lo and behold, does feature in the colour plate in Stubbs & Falk: the yellow patch on the central front part of the frons ('fore-frons') above the antennae. Incidentally I noticed it while trying to hunt for any yellow on what the books and the general consensus calls the 'yellow face', but in fact would be more accurately and helpfully described as a pale cream to yellowish central vertical facial stripe, as opposed to a dark one. Long-winded yes, but I think a better description.
So, back to the fore-frons: this seemed to be the yellowest part of the whole head on all the trivittatus where it showed, indicating that yellow extended from the facial stripe up beyond the antennae a bit, where it was visible from above. This wouldn't be that useful a feature when looking at a specimen as all you had to do was flip the thing and look at the face to see the much larger vertical band, and so wouldn't be mentioned in keys. But it would be useful in the field or photos where you were often looking down on the individual.
Now, there are various possibilities with this feature. One: it is on males only. That would be fair enough and a good extra point. Two: it is only found in some populations. That would be really interesting and worthy of more research. Three: it is unsafe and a proportion of trivittatus are not like the book illustration, but have a dark central fore-frons like the photo under discussion. If this is the case it would be useful to quantify, and at least the feature can be used as part of a suite that together increase the probabilities one way or the other. The one thing you can't do is to ignore or dismiss the feature altogether.
The other feature you mention about the frons, a sharp or graduated border to the ocellar triangle, seems like another excellent field character, and actually backs up my original point: that you can make some conclusions about identity in the field or from photos without actually seeing the facial stripe from the front.
As you say, one of a suite of characters that might prompt you to check the face stripe on a female.
A week of searching and I still have not found a pic showing black above the antennae of trivittatus. Here is a great pic showing exactly the feature I am taking about. I don't know what to call that part or even if is is part of what is called the 'face', but seems to me that it is almost always yellow. Will ask around a bit.
There is also a weird Helophilus on Hants Moths which I will try and get a link to later.
The area you are talking about is a triangular plate which sort of corresponds to the lunula on some flies, though it is not strictly that on hoverflies, as far as I know. You are right that it is pale on trivittatus and darker on hybridus.
Have started a forum thread on Helophilus, but not sure how many will be interested!
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