I] INTRODUCTORY 15 



they became divided into the American and Australian 

 groups. Fleas have been collected on the spiny ant- 

 eater (Echidna) which belongs to the lowest order 

 of Monotremes or egg-laying mammals. 



On almost every form of bird, including the most 

 aquatic kinds, fleas of various species have been 

 obtained. 



Only one instance has been recorded of a flea 

 occurring on a reptile. A female of one of the species 

 of burrowing chigoes (Echidnophaga ambulans) from 

 Australia was collected by Dr Woodward from the 

 Brown Snake (Diemenia sivperciliosa}. This reptile, 

 which is well known in Australia, belongs to a sub- 

 family that contains some of the most deadly 

 poisonous snakes and is allied to the cobras. The 

 Brown Snake is a terrestrial snake, and one must 

 regard the presence of the flea on such a host as a 

 rare and chance occurrence. The snake was captured 

 at Herdman's Lake, near Perth in West Australia. 

 The same species of flea has also been obtained from 

 the phalangers (Trichosurus) which live in the tops 

 of the Australian gum-trees ; from the little terrestrial 

 and nocturnal rat kangaroos (Bettongia) ; and from the 

 banded ant-eater (Myrmecobius), another Australian 

 Marsupial. It is possible that the flea moved from 

 some small mammal which was being devoured by 

 the snake and managed to fix itself between the 

 scaly plates of the reptile. 



