Large multicolour fly and a mining bee for ID please

Dillybythesea · #1 (**permalink**) 12-09-2011, 01:21 PM

Also battling the wind to get to the ivy, along with plenty of wasps and quite a few Colletes hederae, came this fly...

And this bee. Is it Andrena dorsata? Two separate individuals...this one

And this one

JRsbugs · #2 (**permalink**) 12-09-2011, 01:35 PM

Male Tachina fera

Male Colletes hederae I would say, you can see the 's' shaped cross vein.

Dillybythesea · #3 (**permalink**) 12-09-2011, 03:23 PM

Thanks again Janet! I should have known Tachina fera. I don't know why I fell over there!

Please can you explain about the S shaped cross vein? There are lots of C. hederae males about of course, and lots very small, others larger - and all tending to look wonderfully fox-fured over the thorax, so these two threw me with what seemed a much flatter abdomen, and the balding-looking thorax?

JRsbugs · #4 (**permalink**) 12-09-2011, 03:42 PM

It could be the angle making the abdomen look different, and the thorax can often look balding when taken from above when it looks well-haired from a different angle.

I've altered two of your pics a little to show the vein, marked in red.

Dillybythesea · #5 (**permalink**) 12-09-2011, 04:27 PM

Brilliant! That's very good of you Janet. And can I just check, is that indicative of Colletes in general, or just Colletes hederae, please?

JRsbugs · #6 (**permalink**) 12-09-2011, 04:29 PM

It's for Colletes in general.

Dillybythesea · #7 (**permalink**) 12-09-2011, 05:25 PM

Thanks Janet! Noted!

Jason Green · #8 (**permalink**) 12-09-2011, 05:58 PM

Quote:

Originally Posted by Dillybythesea

...so these two threw me with what seemed a much flatter abdomen, and the balding-looking thorax?

Given the apparent depth-of-field, your camera has focussed further down to about the disc of the thorax. The orange hairs in question are still there, just out of focus. It appears to be thicker-haired towards the outside because the lateral faces of the thorax drop fairly steeply and as such you see the sides of their hairs rather than the tops.

What's the S-shaped cross-vein?

Dillybythesea · #9 (**permalink**) 12-09-2011, 08:59 PM

Thank you very much Jason. That clears up a whole lot of worries I was having - like how some individuals look so bald having only emerged two or three days ago. And it makes me think I will have to revisit a lot of older shots taken of bees from above! Yes, I was interested to see the S shaped vein, which Janet has pointed to in red, in her 4.42 posting in this thread. ATB, Rhona