PROCEEDINGS 
OF THE 
Cambridge Philosophical Society. 
A preliminary account of the structure of the mouth-parts in the 
Body-louse. By Launcetor Harrison, B.Sc., Hxhibition 
of 1851 Research Scholar of the University of Sydney, 
Emmanuel College, Cambridge. (From the Quick Laboratory, 
Umversity of Cambridge.) (Communicated by Prof. G. H. F. 
Nuttatu, F.R.S.) 
[Read 21 February 1916.] 
[Plate VIL] 
THE Body-louse is usually referred to as Pediculus vestimenti 
Nitzsch, occasionally as P. corporis Degeer. These names were 
given respectively in 1818 and 1778. ‘The correct name is that 
given by Linné in the 10th edition of the Systema Naturae, 1758, 
namely Pediculus hwmanus. 
The mouth-parts of this insect have a unique interest in 
zoological literature, owing to the controversy which raged for 
many decades as to whether the louse bit or sucked. Inability to 
settle this question was held up as a stock reproach to biologists 
of the first half of the nineteenth century. Schiddte (1866) 
finally cleared up this point, and his account of the method of 
feeding the louse still stands as the best written. But although 
he definitely established the suctorial nature of the apparatus, its 
structure has remained something of a mystery, and its homologies 
have equally remained dubious. Within the last dozen years a 
somewhat bitter controversy has appeared in the pages of the 
Zoologischer Anzeiger, between Professor Cholodkowsky and Dr 
Enderlein, in which diametrically opposed views of both structure 
and homology have been put forward by the protagonists. 
Pawlowsky (1906), a pupil of Cholodkowsky, set himself to clear 
VOL. XVIII. PTS. V. & VI. 14 
