THE FLEAS FOUND ON DO.MEsTIC KATS AND MICE. 



91 



h. Fifth tarsal seoment on eacli side with one heavy sul)-basal bristle, a thinner 

 median one and a small postmedian hair (tig. 5). 



4. E. liopus, Rothseh. Found on rats in India ; originally described from 

 Western Australia, where it is plentiful on Echidna. 



Family II. True Fleas (Pulicid.e). — The rostrum ( = labium + labial palpi) 

 consists o£ four or more segments in the species found on rats and mice. 

 Many species have combs of heavily chitinized spines. The majority of the 

 known fleas belong here. For practical purposes they may be divided into 

 two sections : — 



Section 1. — (Jlab of antenna distinctly segmented only on the hind sido 

 ("hind" side when lying in the groove). — (Section 2, p. 94.) 



Ke^ to the Genera. 



a. Xo comb on head aud thorax. , 



«'. The internal incrassation, which extends from the insertion of 

 the mid coxa into the thorax, joins the anterior edge of the 

 mesosternite (fig-, 6) 4. Puie.v. 



b^. This incrassation joins the upper edge of the mesosternite 



(tig. 7) T). Xenopsylla. 



b. With a comb on the pronotum only , 6. Hoplopsyllus. 



-c. With a comb on the pronotum and at the lower edge of the head 



(figs. 12 & 13) 7. Ctenocephalus. 



k2 



