Technical Abstract: This peer-reviewed web site concentrates on the 66 adult alate and apterous aphids that are the world's most cosmopolitan and polyphagous species. The site includes fact sheets about the various aphids species, a glossary of terms helpful to the student, hundreds of photographs and illustrations, and an interactive key for identification. The interactive key is designed on the LUCID expert system for identification. This system allows the user to select characters to start an identification or the user can allow the LUCID system to select "best characters" for rapid identification. This paper will be of special interest to quarantine personnel at both the federal and state levels, academic teaching institutions, and insect taxonomists.