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THE AMERICAN NATURALIST [Vol. XL VIII 



records are my own. One is a new species of Colpoce- 

 phalum (exclusively a bird-infesting genus) from a 

 ' 1 spotted rat/' Uganda, Africa, sent me by Sjoestedt in 

 a collection made by the Swedish Zoological Expedition 

 to Kilimandjaro-Meru, Africa, in 1905-1906. It is un- 

 doubtedly a straggler from some bird taken at the same 

 time. The other is a poor specimen of Trichodectes from 

 Mus rattus, Canal Zone, Panama, sent me by Dr. Jen- 

 nings. It may be a good record — or it may be a deceiving 

 one. Both record and specimen need further scrutiny. 

 It is, perhaps, important to note that two specimens of 

 a wingless Psocid (Atropidae) were sent with the lot 

 labeled "parasites from Mus rattus." It would be very 

 interesting if we could know that these Atropids were 

 really living on the rats, feeding on their hair or dermal 

 scales. I have found Atropids in rats' nests and birds' 

 nests living undoubtedly on the loose hairs, feathers and 

 dermal exuviae. It is my belief, based primarily on cer- 

 tain striking facts of morphology, that the Mallophaga 

 are degenerate descendants of the Bsocidae. 3 Of the 

 murid Anoplura, two or three are common to several 

 hosts, as the well-known Polyplax spinulosa, recorded 

 from all over the world from the now cosmopolitan Mus 

 rattus and Mus decumanus, as well as from Mus syl- 

 vaticus of Europe and north Asia, and Mus alexandrinus 

 of south Europe and Asia Minor (perhaps only a variety 

 of Mus rattus), and Polyplax affinis (perhaps only a 

 variety of P. spinulosa) recorded from Mus agrarius of 

 eastern Europe, and Mus sylvaticus of Europe and north 

 Asia. Polyplax (Hoploplcura) acanthopus, the common 

 sucking louse of the mouse has been taken from the now 

 cosmopolitan Mus musculus, and also from Lemmus tor- 

 quatus, the lemming of Arctic Europe, Asia and America, 

 Microtus agrestis, the field vole of Europe, Microtus arva- 

 lis, another common vole of Europe and Asia, and Micro- 

 tus sp. from Iowa, U. S. A. The water rat, Hydromys 

 chrysogaster, of Australia, has a Polyplax species of its 

 own as has also Ototnys bisulcatus of south and central 



3 See Psyche, Vol. 9, 339, pp. 1902. 



