GENERA OF PULIGIDAE 455 



First hind tarsal segment with less than five bristles which reach 

 to the apex of the second segment . ',.-,- . u 

 u. Rostrum longer than the maxillary palpus . ^ . . . mycerini. 

 Rostrum as long as the maxillary palpus ; upper process of the 



clasper ( ^ ) broad, truncate . . .-',' . ';. ramesis (and 



conformis). 



Of these, all have been found in Egypt except creusae and scopulifer, 

 which are South African. Nubicus was taken on Mus macleari on 

 Christmas Island. 



The synonomy of cheopis is as follows. Pulex cheopis, Rothschild, 

 1903. P. brasiliensis, Baker, 1904. P. murinus, Tiraboschi, 1904. 

 P. Philippine-lists, Herzog, 1904. It used to be referred to as Pulex 

 pallidus, Tasch., in plague literature. The figures on Plate LV will 

 assist in the identification of this species. 



GENUS RHOPALOPSYLLUS, BAKER. 



This genus is exclusively American, and includes fleas found mostly 

 on small rodents, such as weasels, opossums, peccaries, and ground 

 squirrels. Some of them may prove to be of importance in connection 

 with plague in the localities in which they occur. 



GENUS LYCOPSYLLA, ROTHSCHILD. 



This genus, for which a new family has been proposed by Baker, is 

 distinguished from Pulex by the presence of a small sinus on the front 

 of the head (Plate LVI, fig. 5), closed in anteriorly by a distinct tooth. 

 The seventh abdominal tergite has no apical bristle. One species, novus, 

 Rothschild, is known, from the Australian Wombat, Phascolomys 

 mitchelli. 



GENUS HOPLOPSYLLUS, BAKER. 



A genus of North American fleas, mostly occurring on rabbits, though 

 on one occasion H. anomalus has been found on a rat. Baker gives its 

 host as Citellus (ground squirrel, California). The genus resembles Pulex, 

 but is sharply distinguished from it by the presence of the pronotal comb. 



GENUS CTENOCEPHALUS, KOLENATI. 



In this genus are contained the cat and dog fleas, frequently con- 

 founded with one another, or regarded as the same species. The distinc- 

 tion may perhaps prove of interest in connection with Kala Azar. The 

 points on which they are separated by Rothschild are as follows. In 



