The lily and the fly

 

 

Eric and I came across a nice patch of Death Camas or Fremont's Star Lily (Toxicoscordion fremontii, formerly Zigadenus fremontii) recently.  Eric wondered what might pollinate them.  I wasn't sure, but I had seen flies pollinating other lilies, so we started to look around.  

As we kneeled down for a closer view, we started noticing some small flies nestled among the petals of the lilies, and sometimes they'd rest out towards the tips:

 

  

With a zoomed in view, you could really see the pollen grains on the flies, especially on the thorax and the eyes:

 

 

Eric did a little research and narrowed down the identification to a group of hoverflies, perhaps in the genus Cheilosia.  These flies are sometimes referred to as "blacklets."  [If anyone knows more about these flies and can confirm the i.d., we'd appreciate any assistance.]

Here's another view, this time from the side.  It's fun to think about what a nice spot these flies have for feeding and resting as well as the assistance they provide to the lilies!