Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Gregory Paulson's site with thumbnails of over 6500 SEM images of various organisms, mostly insects.
http://webspace.ship.edu/gspaul/Scanning%20electron%20micrographs%20%28SEM%29%20of%20insects%20and%20other%20arthropods.html