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ON A NEW GENUS AND SPECIES OF SIPHONAPTEEA 

 FROM NYASALAND. 



By the Hon. N. Charles Rothschild, M.A., F.L.S., F.E.S. 



The Entomological Research Committee has received from Zomba four 

 specimens of a new species of flea which is related to the genera Leptopsylla, 

 Roths. (1911 ; type musculi, Duges, 1832) and Palaeopsylla, Wagn. (1902; 

 type minor. Dale, 1878 = gracilis, Tasch., 1880) but differs so much from the 

 species belonging to these genera that it requires a separate genus. The 

 species is especially remarkable for the development of its head and buccal 

 organs (fig. 1). The mandibles as well as the labrum are very broad, particu- 

 larly the former, and closely resemble those of Spilopsyllus cimicvJi, Dale (1878), 

 and the Saecopstllidae. This peculiar parallelism also obtains in the labial 

 palpi, which show a reduction similar to that which occurs in the fleas mentioned, 

 being but feebly chitinized and consisting of only three distinct segments. The 

 size of the labrum and mandibles suggests that the species fixes itself to the 

 host by means of these organs in the same way as Spilopsyllus cunicwli, i.e., 

 more permanently than do the majority of fleas. The structure of the head 

 bears out this surmise inasmuch as the buccal slit extends far upwards, the 

 frons being short, which allows the piercing organs to assume an almost 

 horizontal position when being driven into the skin of the host. 



The new genus, which we propose to call Chimaeropsylla, gen. nov., is further 

 characterised by the first segment of the mid tarsus being one-fourth shorter 

 than the second, and the first of tbe hind tarsus as long as the second segment. 



Fig. 1. — Head of ChiinaeropsijUa potis ,J. 



