VII - On the internal anatomy of the larva of the Rat-flea, Nosopsyllus fasciatus (Bosc)

Abstract Although a very extensive literature, covering a period of many years, exists on the anatomy of the flea larva, most of it deals only with the external anatomy. Previous studies on the internal anatomy are few and scarcely sufficiently detailed to throw any light on the affinities of the order Siphonaptera. It was therefore considered desirable that the whole question of the internal anatomy of the flea larva should be revised in the light of our existing knowledge of insect morphology. Consequently, a detailed study of the internal anatomy of the larva of fasciatus (Bose) was undertaken to elucidate the various anomalies in the internal anatomy of the flea larva, and, if possible, to throw some light on the systematic position of the group. In order to complete the account of certain systems, a partial account of the prepupal stage has been included so as to facilitate the proper understanding of the pupa, an account of which is to follow. The figures illustrating this paper are all camera-lucida drawings and have been finished by me in ink. In my description I have used the same terminology as is used by Snodgrass (1935) in his recent book. The specific names of fleas given in this account are corrected up to date by following the nomenclature adopted by Jordan (1933) and Wagner (1930).