ORDER SIPHONAPTERA (APHANIPTERA) : FLEAS 197 



Genus Pygiopsylla, Rothschild. Two species of this genus 

 are recorded by Rothschild from rats, and both are said to 

 be common in Australia. The genus is characterised by its 

 peculiar convex pygidium, the posterior edge of which 

 projects free. 



Genus Chiastopsylla, Rothschild. Distinguished from 

 Ceraiophyllus by having two teeth at the angle of the head 

 behind the maxilla. Rothschild mentions one species from 

 a rat from South Africa. 



Genus Ctenophthalmus, Kolenati (Fig. 8i). The eyes are 

 vestiges, and there is a comb on the lower edge of the head 

 and also on the pronotum : there are three antipygidial 

 bristles on either side. C. agyrtes, found on the brown rat in 

 Europe, has sixteen teeth in the pronotal comb, and three in 

 the genal (head) comb. Other species have been found in 

 America and South Africa. 



■max.p. 



Fig. 81. — CtenopUlialmus. 



FlQ. 82. — Ctenopsylla. 



Genus Neopsylla, Wagner. One species, having two teeth 

 at the genal angle, has been taken from a rat in Russia. 



Genus Ctenopsylla, Kolenati (Fig. 82). The species are 

 readily distinguished by the close-set, almost comb-like, row 

 of bristles on the hind edge of the tibiae. The head is sharply 

 conical and has a comb, as has also the pronotum. C. musculi 

 is of common occurrence on rats and mice in many parts of 

 the world. 



Genus Hystricopsylla, Taschenberg. The species of this 

 genus are large and hairy : the head is conical, eyes are 

 absent or vestigial, and some of the abdominal terga, as well 

 as the cheek and pronotum, have a comb of teeth : the 

 bristles of the posterior edge of the tibia are set in numerous 

 close, transverse rows — three or four bristles in each row. In 



