See the November 1, 2002, Ferminews article for more details.  (Available online at http://www.fnal.gov/pub/ferminews/ferminews02-11-01/p3.html) 

In 2003, we failed to find any adult butterflies in the release area, so this attempt to establish the Silver-bordered Fritillary here seems to have failed.  It may be that these caterpillars were too far along in their development to overwinter.  When we have an opportunity, we may try again. 

Here is what we looked for in the spring and summer of 2003 where the caterpillars were released.  Although the upperside looks very much like that of the Meadow Fritillary, note the silver spots on the underside, which the Meadow Fritillary lacks. 

Incredibly (both in that it was there and that I was lucky enough to spot it and photograph it), I photographed this Silver-bordered Fritillary as it paused briefly to nectar in my back yard in Saint Charles.  I do not know where it came from.  Maybe there is a nearby population that I do not know of, for example near the Fox River a few miles to the east.  It came into my yard from the east and flew away strongly to the west.