Flea systematics is based on morphology with the majority of characters derived from the extraordinarily intricate genitalia. Fleas are one of the few insect groups for which it is easier to identify specimens to the generic level than to family, and molecular data suggest that most of the flea families are in fact paraphyletic. Identifications require an extensive knowledge of flea morphology and experience in viewing many specimens. Molecular data is shedding new light into these groups, and in the end will certainly change how we view flea classification.
It is our intention to provide a complete source to flea systematics on this site, with tutorials in flea morphology, fully illustrated taxonomic keys, collection data bases, extensive photo documentation of each species, and the most up to date information on flea phylogeny and character matrices, both molecular and morphological. This is a large collaborative project that we anticipate will take 5 years to complete.