The "checklist of Washington butterflies" has been revised and expanded and is now titled the "Summary of Washington Butterflies". It includes a very helpful foodplants list in addition to the updated county checklist and taxonomy!
The list of updates to the Butterflies of the Pacific Northwest book has also been updated to include notes about the newly described species Celastrina asheri and I added a link to that paper and also Todd Stout's paper about the Anthocharis complex (orangetips) which includes a range map. I occasionally get questions about Sara's vs. Julia's orangetips and what occurs where, so I thought this would be a good reference for people.
You will find these updates available for free download here: