We get a lot of requests to identify bees and their pests. This blog article links to three different databases that can assist you in your research.
Bee Informed: Protect Bees from Disease, Master Melittologist Program, Bee Identification
Another option is to do an image search on your favorite browser? If you don't know how you can query "How to do an image search."
Our Capped-End Guide for Cavity-Nesting Bees can help you determine what may have taken up residence in your bee house.
Parasites and Diseases of Mason Bees offers some help in identification as does Parasites and Diseases of Leafcutter Bees.
Additionally we offer the following books on our website that may be of help:
Common Bees of Western North America - Identification Guide
Field Guide: Bees of the Puget Sound Lowlands
The Bees In Your Backyard
Common Bees of Eastern North America - Identification Guide