Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

This is routinely updated and each draft is numbered.
The current version is Draft-38, 14 January, 2014 (the year for this draft can be cited as 2014 not 2011).

thanks -- edited

Latest update: Draft-49, 20 October, 2017
Here is the correct link to the guide based on my data compilation:

The above-cited link goes to the generic "bee" page that links to ID nature guides, etc.