Phillip,
If you've deleted the URLs, there's not much else for you to do. You're experiencing the lag between when Google crawls and indexes pages new pages and when it finds and removes a 404 URL from it's index.
You should think 90 days as an approximate time frame for your page count in the index to start dropping. Here's more from google:
https://support.google.com/webmasters/answer/1663419