Pawpaws and flies

[Hank Roberts]

Following up on the factoid about the Shawnee knowing only 'green flies' --
I was a national park summer ranger in the Black Hills some years back
and the older houses there were built without screens for the windows;
the longtime residents said that while the area was still fairly wild they
had no significant problems with flies -- but once the cattle started to
be run in the area (1930s?) the flies came also.  I find that believable.