I've noticed (and photographed) these too. The flies appear to be encouraged to enter the flower to get their goodies and in so doing, have to pass these curtain affairs. My guess is that they sweep off any pollen present on the visitor and move it to where it's wanted. Most flower pistils have similar arrays of sticky-out bits that transport captured pollen to the middle and thence down inside the pistil tube. I'm no botanist and so could be talking utter bilge!

I approached this as a potentially easy job. I had left a couple of parsnips to go to seed in the garden (because I didn't know what one looked like) and there they were, right in front of a dark painted fence. Each individual flower was glistening with tiny globs of nectar. The first problem was the breeze. Even when I stuck a cane in to tie it up it still swayed about. Several failed snaps later I was up to ISO800 and speeds of over 1/1000.

Patience got there in the end and I got a series of closer and closer shots, stopping down all the time to about f20 at the end.
Here's a parsnip flower head - not your average cow parsley.



and a bit closer



and closer



And I've seen maybe two bees a day on it. This is a worrying year.
K1 with a Kiron 2.8/105 macro lens.

Goes to show - you don't even need the sun ! Nice.

It can be done but sooner or later you will remove the lens and the adapter will stay in the camera. It can be more trouble than you might expect. Once you get used to it you will almost certainly get more lenses from E bay - M42s are not expensive and it's fun to try them out.

I have also noticed these little black bees(?) and I can't find any reference to them. Anybody know what they are? I wouldn't accuse it of photo bombing (even if it did) because it transforms the shot.

I like the second one due to its sense of mystery. The first one is a foregone conclusion. That said, both are a good use of the lens.

The first one is gorgeous. The other two look a bit steep!

If you bite your nails then you are out of luck and will need a ball point pen. Otherwise, the genuine adapter can be removed by sticking your thumbnail into the slot at the 10 o'clock position to release the spring. Do not over tighten the lens to get the index mark precisely lined up (it's tempting when it's half a degree out). It will be a bugger to get off again! Putting the thing onto the camera, it is 'obvious' that you shove the red dot to the red dot and then try to push the opposite side of the adapter into the mount. Surprise - it won't go. Think about it and ignore the dot (other than for positioning it). The spring has to be compressed before the rest of it will go into the mount so shove the bit with the spring in first. The remainder simply slots into place.
Some M42 mounts - like Tamron twin tele, Meyer 135 and 200mm, Tair 300mm do not snug up to the camera when screwed on and they leave a tiny gap where the two slots on the adapter will admit light. It doesn't always happen but when it does it can be very hard to diagnose the problem. Once you realise where the light is getting in a tiny bit of tape cures it instantly.

Wow. Some talent on display there!

Ah - being withered it needed more oomph.