Vol. 48, pp. 201-210 November 15, 1935 PROCEEDINGS OF THE -^^^IUHisi5/g|^j^^,Q^L SOCIETY OF WASHINGTON APR 2iS33 ^ TAXONOMY OF THE ANOPLURAN GENERA POLYPLAX AND EREMOPHTHIRIUS, INCLUD-ING THE DESCRIPTION OF NEW SPECIES. BY H. E. EWING, Bureau of Entomology and Plant Quarantine, United States Department of Agriculture. The anopluran genera Polyplax Enderlein and Eremophthirius Glinkiewicz are very closely related. Together they constitute a natural group of the subfamily Hoplopleurinae, family Haematopinidae, which parasitize exclusively hosts of one family of rodents, the Muridae, and of one family of insectivores, the Soricidae. The group is widely distributed, being found on all continents except Australia. It is best represented in Africa, where 16 species are known. The occurrence of species of Polyplax on shrews (Soricidae) is of special interest. A number of such records have been made; yet for only one species is there convincing evidence that shrews are the true hosts. There are many records of the occurrence of Polyplax reclinata (Nitzsch) on shrews in Europe and Asia, and no records of this species from other kinds of hosts. These shrews belong to four different genera and are widely distributed. This shrew-infesting louse is so near to the type species that it is dis-tinguished from the latter only by very trivial, yet constant, characters. Its unusual host relationship, therefore, is not associated with any unusual morphological character. Its characters are unmistakably those of a murid-infesting louse, of lice that evidently evolved on and with murid rodents. We have no evidence that Polyplax evolved upon insectivores. Lice of insectivores, as far as known, are of a type quite different from Polyplax. Thus we are forced to conclude that not very far back in geo-logical history the ancestor of Polyplax reclinata must have "bridged the phylogenetic gap" between murid rodents and insectivores, in crossing over from hosts of the former group to those of the latter. 38— Proc. Biol. Soc. Wash., Vol. 48, 1935. (201)
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