The taxonomy of fleas is a complicated process and a good deal of expertise is required to identify most taxa to the species level. Moreover, unlike other insect groups, it is very difficult to identify fleas to the family level, and it is generally easier to identify flea genera than flea families. To complicate matters more, subgeneric and other "groups" are commonly recognized for many taxa.
Our intent is to produce working keys for flea identification, with extensive documentation of the characters used in the couplets, and examples of as many species as we can acquire through our efforts. This is an extensive project, and we are currently compiling these keys. Other than the key to the subfamilies of Hystrichopsyllidae, the keys presented here are extracted from the work of G.H.E. Hopkins and M. Rothschild. 1962. An Illustrated Catalogue of the Rothschild Collection of Fleas in the British Museum (Natural History), Volume III: Hystrichopsyllidae, London, 560 pp., 1,049 figs., 10 plates. Line drawings are from the same source to which we have added photos for further illustration.