110 THE FLEA 



of five, or more, segments inclusive of the unpaired 

 basal one. Thoracical tergites together longer than 

 first abdominal tergite. 



Here belong the majority of Siphonaptera. 



III. Family Ceratopsyllidw. Baker (1905). 



Head on each side with two flaps situated at the 

 front oral corner. Here belong the bat-fleas only. 

 There are several genera, and about twenty-five 

 species have been described. In most of the bat- 

 fleas the maxillae are shaped like a dumb-bell, but 

 in the genus Thaumopsylla they are triangular as in 

 the Pulicidw. 



Oudemans (1909) has put forward an alternative 

 classification of the order Siphonaptera based on 

 the morphology of the head : I. Integricipita, 

 II. Fracticipita. 



APPENDIX B 



A LIST OF BRITISH FLEAS AND THEIR HOSTS 



A list of the British Fleas (Siphonaptera) revised 

 to March 1913 : 



Names Usual Hosts 



PlTLEX, L. 



P. irritaus Man, Badger 



XENOPSYLLA, Glink. 



X. cheopis, Rothsch. Rat 



