I can see both males and females in this photo. Males eyes look like they touch at a point whereas the females eyes are wider apart.

I always look at the eyes of syrphids, bee flies, march flies, etc. but it didn't occur to me to look at these. In many fly species there is no difference in eye size between the sexes, but here it is crystal clear. Very nice.

Thanks, Mike. I just neutered the whole pile.

I think that females are attracted to the smell and try to lay eggs on the rotten flesh or fecal matter (sneaky stinkhorn, it exploits the flies as spore carriers). Whether males come too looking for females to mate with, I don't know.

Is it ID'able? It's to the upper left of the fly in the center.

Hi Nancy,

Some fly expert might be able to do something with it (maybe to family?), but I think I'm going to consider the report list closed, as reformatting it at this point would be a bunch of work and I'm under the weather. :( The IDs are likely to shift a bit in time anyway, so the report will never be perfect.

If someone wants to comment on that tiny fly and think that it will be helpful to inform the park service, I'll be happy to do so.

Thanks!

The truth is, Mike, I don't remember if I had help or if I made that call alone on the basis of the number. It makes sense that I might have made the call, operating under the assumption that there were both males and females. Now that you mention it, that is not a reasonable assumption. Shall I edit the identification or wait to see if someone has a rationale that really permits making the claim that both males and females are present?
Thanks for helping to hold me/us responsible.

I guess I would remove those checkboxes until someone can come along and state it decisively. Thanks!

worse than the things that blowflies normally love to land on.

When I saw it, it was covered in dark brown, with very little white showing!