APHANIPTERA. 349 



" There is something very remarkable about the manners of fleas ; 

 the mother flea disgorges into the mouth of the larva the blood 

 with which she is filled " ; and Van Beneden, in Vol. xix. of the 

 International Science Series, 1889, says, "The larvae of fleas live 

 only on what the full-grown insect brings them ; the mother flea 

 sucks for herself first, and then divides the spoil with her larvae." 

 The stories are copied from one book to another, but as the author 

 rarely or never informs us that he writes from personal observation, 

 I think these statements require confirmation. According to Van 

 Beneden it is probable that the dog flea is the intermediate host 

 of the tape-worm common to that animal. 



The fleas are all comprised in the two families Sarchopsyllidce 

 and Futicidce. Passing over for the present the first of these, which 

 contains only a few species, and none of them being found in this 

 country, and adopting the classification in Verrall's list, we have in 

 Britain three genera — Fulex, Hystrichopsylla, and Typhlopsylla. 



The common flea, P. irritans, is sometimes regarded as the 

 only species of the genus Fulex, and the rest are ranked under 

 other genera; but this seems rather in honour of man as being the 

 host of the first-named flea than from any real difference. 



Fleas may be classed as follows : — 



a. Eyes distinct — Genus Fulex (in Britain about seven species). 

 aa. Eyes wanting or rudimentary — Hystricopsylla (one species) 



and Typhlopsylla (four species). The chief genus Fulex 

 can be sub-divided. 



b. No spines on back or head — F. irritans (man). 



bb. Spines on back only — Comb with 18 teeth: F. fasciatus 

 (rat), F. melts (badger), F. sciurorum (squirrel). Comb 

 24 to 26 teeth — F. avium (birds). 



Under side of head with spines : 7 to 9 spines — F. serrati- 

 ceps (dog, cat) ; 2 spines on cheek — P. erinacet (hedge- 

 t^og) ; 5 to 6 on each cheek — F. goniocephalus (rabbit). 



Eyes wanting Typhlopsylla : 3 spines on cheek —Assimilis 

 (mole). 



The slides and photo-micrographs that I have brought to 

 illustrate this paper are chiefly of F. goniocephalus, which I found 

 in great numbers inside the ear of a rabbit. This species was 



