NOTE ON THE MOUTH-PARTS OF LICE. 



By LAUNCELOT HARRISON, B.Sc, B.A., lecturer and Demonstrator in Zoology, 



University of Sydney. 



(With a Figure in the text.) 



In the course of an account of the mouth-parts in the Body-louse, Pediculus humanus L. (Harrison, 

 1916), I endeavoured to bring these structures into correlation with those of the Mallophaga, a group 

 of orthopterous origin. Such an interpretation is quite contrary to the generally accepted view, which 

 would ally the sucking lice — Siphunculata — with the Hemiptera. The most recent expression of this 

 latter view is that of Enderlein (1904, 1905), who finds no difficulty in homologising the piercing 

 apparatus of the louse with that of the bug. In my paper, quoted above, I have criticised Enderlein's 

 views, and set out my own, at some length. 



At this time I was acquainted with only one species of Mallophaga which suggested a condition 

 in any way intermediate between biting and sucking mouth-parts. This was Philandesia townsendi, a 

 parasite of the South American rodent, Lagidium peruanum Meyer, described by Kellogg and 

 Makayama (1914). In their diagnosis of the genus (1914, p. 198), the authors write : — 



" Mouth-parts (Text -fig. i.) of unusual type, the mandibles being long and slender and the other 

 mouth-parts, together with the hypopharynx and pharyngeal skeleton, forming a sort of grasping tube 

 or furrow." 



I have since received, through the kindness of Mr. G. F. Ferris, of Leland Stanford University, 

 specimens of Philandesia, and am convinced of the importance of this species as an intermediate type, 

 the mouth-parts of which are modified in the direction of sucking. I have not yet, however, had the 

 opportunity of making a detailed examination of the mouth apparatus. 



A second point of interest in connection with Philandesia lies in the fact that it is a two-clawed 

 Amblyceran parasite of mammals. Outside the family Boopidae, confined to marsupials of the Australian 

 region, only one other such genus is known, namely Trimenopon, Cummings (1913), also from a South 

 American rodent, which I have included (1916 a, p. 31) with Philandesia in a family, Trimenoponidae. 

 A third family, Gyropidae, of Amblycera, is also found upon mammals, and again almost entirely upon 

 American rodents. 



The peculiar distribution of these three families of mammal parasites, which are more nearly 

 related to one another than to the bird-infesting Amblycera, led me to question whether the American 

 forms might not be derivatives from the American marsupial fauna, from which no Mallophaga have 

 been described. In order to try and settle this point, I examined a number of skins of American mar- 

 supials in the British Museum, and was successful in obtaining from two species of Peramys, a small 

 rodent-like marsupial, a Mallophagan form closely related to Philandesia and Trimenopon, but generically 

 distinct. As this occurred in fair numbers, there is no reasonable doubt but that it is an actual parasite 

 of the genus Peramys. The only other Mallophagan found during the examination of skins of several 

 species of marsupials, was a single Gyropus from Metackirus, upon which no conclusions can safely 

 be based. 



The chief interest of the new form centres in its mouth-parts, which differ from those of Philandesia, 

 but which also show an intermediate condition. The mouth is a transverse slit, the labium, notched in 

 the middle, but not grooved as in Philandesia, completely covering the weakly chitinised mandibles. 



