Siphonaptera are better known as fleas. The Museum's collection is large and has great historical importance.
The Museum’s collection of fleas is estimated at 260,000 specimens, representing 73% of the 2,587 described species and subspecies of fleas including 925 primary types.
The geographical range of the collection is worldwide and the bulk of the specimens are mounted on microscope slides. The remainder are stored in fluid.
The centre of the Museum’s collection is the Rothschild collection of Siphonaptera, given as a deed of gift in 1913. It was not registered as Museum property until 1923, when Charles Rothschild died.
A seven volume 'Catalogue of the Rothschild collection of fleas' was published by the British Museum of Natural History between 1953 and 1987.