Colias in fight

Yes, I definitely agree with your "capturing impossible..." statement.  Getting the bf even reasonably sharp is quite a feat.  In this case you got the curled proboscis nicely sharp and the eye reasonably sharp.  Interesting that this summer I too spent quite a bit of time going for close-up, in-flight shots.  It's a great way to generate a lot of throw aways, with the few shots like this providing the tantalizing results that keep you trying again.

Wonderful subject!   If you have photoshop and a few sharpening skills, plugins...you could bring out even more detail.  
One thing to try on impossible shots is to convert them to Art....   I do this a lot, when the photo isn't quite right, and the results can be spectacular.  Play around in photoshop and use Topaz or other interesting plugins and have a ball!  In fact, I just converted a photo of a bee on a yellow flower (Weekly Challenge) and posted it today.  I used the Topaz Impressionism program and made it look like an oil painting....who expects an oil painting to be razer sharp?  Nobody!  LOL  And I loved the result!

Freezing a butterfly is no easy task ..as they can take off or land in from any direction.To get the face sharp is a double plus. very well done

Balan Vinod