672 Laura Florence 



interpretation of the mouth parts. Owing to the specialized nature of 

 the mouth parts and the lack of any ontogenetic proof of their homologies, 

 various interpretations have been offered by investigators according to 

 their views of the affinities of the group. 



The early naturalists of the latter half of the seventeenth century 

 attributed sucking mouth parts to lice, and based their opinions on the 

 experimental feeding of captive hce on themselves. Nitzsch (1818:304) 

 confirmed the observations of Swammerdam as to the pre.sence of a 

 bristle sheath (not the true sheath, but the proboscis), and put forward 

 the hypothesis that the inner tube of suction consisted of several setae. 

 His drawings of the structure were published, not with the text, but 

 posthumously by Burmeister (1838). A year later Erichson (1839:377) 

 stated that previous workers had erred in their descriptions, and that 

 the louse possessed no hooks on the haustellum but did have a pair of 

 strong, four-jointed palpi and very distinct mandibles. This statement 

 led to Burmeister's (1847) paper upholding and confirming the opinions 

 of Nitzsch, in which he gave an account of the structures in the hog louse. 

 His work, though in the light of more recent investigations incomplete and 

 in parts inaccurate, was a distinct addition to the knowledge of the subject. 

 It was followed the next year by a contribution from Simon (1848:274), 

 who, in his treatise on skin diseases, described his joint work with Erichson 

 and corroborated Erichson's statements as to the presence of true palpi 

 and mandibles and the absence of a sucking apparatus. 



The controversy was finally settled in 1864, when Schjodte (1864, English 

 trans. 1866:213) published the results of 'his investigations and his inter- 

 pretations of the artifacts which had misled the supporters of the biting- 

 mouth-parts theory. In the same year Landois (1864 : 3) described the 

 mouth parts of Phthirius as corresponding very closelj" with Erichson's 

 and Simon's descriptions of those of Pedicuhis capitis and P. vestimenti, 

 but when he published the results of his investigation of the clothes 

 louse (Landois, 1865 a; 34) he stated that his first interpretation was 

 wrong and that the mouth parts were of the sucking type. BruM (1871) 

 described the mouth parts of the three species affecting man, and 

 along with Schjodte considered the piercing mouth parts as having arisen 

 through a modification of the mandibles and the maxillae, a view which, 

 according to Endcrlein (190.5:631), originated in 1853 with Gerstfeldt, 

 who regarded the mandibles as a tube made up of two halves antl the 



