I.D. night flying Moth?

[Croaton]

After dusk tonight I saw in my garden a moth that is as large as a woman's
thumb with a wing span to match or somewhat larger.  It was hard to tell if
there were two sets of wings.  I suspect there were.  It was feeding on nectar
of the petunia.  It had a tongue as long as its body and antennae that looked
feathered.  It appeared to have black and greenish yellow bands on its body. 
In profile it looked like a hummingbird and it fed in the same manner, but this
was no bird!  I am familiar with the Hummingbird Moth and see them in my garden
during the day.  This was just before it was too dark to see.  I live in
Illinois.  Can anyone identify this?