406 THE ANIMAL PARASITES OF MAN 



[The chief genera and species of British Pulicidce may be tabu- 

 lated as follows : 



(1) Pulex : Eyes distinct. 



(2) Hystrichopsylla : Densely spinose cheeks and clypeus. No eyes, or 



eyes indistinct. 



(3) Typhlopsytta : Body narrow and elongated. No eyes, or eyes 

 indistinct. 



(1) Pulex. 



No prothoracic posterior comb . . . . . . . . irritans. 



Posterior comb present. 



Head without black spines. 



Prothoracic comb with twenty-six teeth . . . . gallince. 



Prothoracic comb with eighteen teeth . . . . fasciatus. 



Head with black spines. 



Cheeks, &c.,with six or seven black spines on each side canis. 



(2) Hystrichopsylla. 



Cheeks and clypeus densely spinose . . . . obtusiceps. 



(3) Typhlopsytta. 



Comb only on posterior margin of pronotum. 



Four genal spines . . . . . . . . . . musculi. 



Three genal spines . . . . . . . . . . assimilis. 



3. Sarcopsylla gallinacea, West wood (The Chigoe of Fowls). 



This flea is a native of Ceylon and N. America. It lives on 

 the fowl chiefly, attacking the neck and around the eyes. Speci- 

 mens were sent me from Texas, where they not only attack 

 poultry but also children, the latter somewhat severely. It also 

 occurs on cats. 



4. Pulex serraticeps, Gervaise (The Common Cat and Dog Flea). 



In the eastern cities of America the cosmopolitan dog flea is 

 the species that overruns houses. Man is badly bitten by this 

 species in most parts where it occurs. The eggs are deposited 

 amongst dust, clothes, &c., and hatch out in fifty hours amongst 

 the dogs' and cats' hairs. As they are not fastened to the hairs 

 they fall off. The larvae live seven days and then spin a cocoon 

 amongst the dust and dirt. They remain in the cocoons eight 

 days. The times are variable, however, for Howard and Marlatt 

 show that the eggs hatch in one day and the larvae commence 

 to spin in from seven to fourteen days after hatching, and the 

 flea appeares five days later. The changes thus observed in 

 Washington agree with those observed by Simmons in Calcutta. 



