My friend, a fellow Vanagon owner, came up with this great idea for a screen
for the rear hatch of a Vanagon.  Total cost about $15.00.
Materials:Purchase mosquito netting (make sure its big enough) for about $10
form an army/navy store.  Next get about 10 feet of shock cord and two snap
on clips for the ends.  I got mine from a boating store.
Best installed with two people-one holds the netting in place in the open
rear hatch.  Clip the two ends of the shock cord together so you have a
giant rubber band.  This slips nicely over the netting and onto the lip that
the black weather-stripping is attached to.  You will then have a nice no
holes drilled installation that is bug proof. Trim to size and it looks good
in & out.
-Mike