ON TWO NEW LICE. 245 



21, On Two New Species of Polyplax (Anoplura) from 

 Egypt. By Bruce F. Cumbiings *, British Museum 

 (Natural History) f. 



[Received January 26, 1915; Read March 23, 1915.] 

 (Text-figures 1-16.) 



Index. 



Page 



Structure or Morphology 249, 255 



Development 260 



Si'stematic : 



Polyplax brachyrrhynchus, sp. n 246 



Polyplax oxyrrhynchus, sp. n 251 



Introduction. 



The following descriptive paper on two species of Polyplax is 

 based on a large supply of spirit material collected on Acomys 

 cahirinus Geoff. (Family Muridee), at Assiut, in Egypt, and 

 forwarded by the Department of Public Health in Egypt to 

 the Lister Institute of Preventive Medicine, by whom they 

 were subsequently presented to the British Museum through 

 Mr. A. W. Bacot and Dr. G. F. Petrie. Both these species, 

 which are new, were fortunately collected in large numbers 

 in all stages of development, and it has been possible to present 

 an account of the larvse and also of several features of interest 

 in the internal anatomy of the imagines ; unfortunately, the 

 specimens were so badly preserved as to make a study of the soft 

 parts out of the question. 



It is to be hoped that in future collectors will bear in mind the 

 extreme value to systematists of a long series of specimens of 

 the same species, particularly in the case of ectoparasites like the 

 Anoplura and Mallophaga, where so little is yet known of the 

 morphology, metamorphosis, and variation. 



Polyplax oxyrrhynchus was the more numerous species, there 

 being 918 adults besides numerous immature forms, as compared 

 with only 360 P. brachyrrhynchus, of which 75 were immature. 

 Both these species, which are quite distinct, were collected on 

 the same host. 



Associated in the tubes with these, and, according to the label, 

 collected on the same host, were several fleas, one or two Psocids, 

 many mites, and a Muscid fly. 



The Hon. N. C. Rothschild has kindly identified the flea for 

 me as Xenopsylla cheopis Roths., and my colleague, Mr. A. S. 

 Hirst, refers the mite to Dermanyssus cegypticus Hirst. 



The fly and the Psocids are probably only accidental inclusions. 



* Communicated by the Secretary. 



f Published by permission of the Trustees. 



