674 Laura Florence 



This Biiggcstion was criticized by Enderlein (1904:121 and 1905:626), 

 who. believed that these insects were hemipterous in their affinities, and 

 consequently liomologized the piercing apparatus with the maxillae, 

 hypopharynx, and labium of the Rhynchota. His method of investi- 

 gation was by gross dissection and by the study of cleared and mounted 

 specimens. He used a number of related forms but gave the most detailed 

 work to the interpretation of the hog louse. He compared the "mandi- 

 bles " of the latter with those of the Corixidae, a proceeding which led 

 to a discussion of the question by Handlirsch (1905:668), who emphasized 

 the much clearer resemblance existing between the mandibles of the 

 Siphunculata (Anoplura) and of different species of Mallophaga as figured 

 by Snodgrass (1899). One outcome of the controversy between Cholod- 

 kovsky and Enderlein was the publication by Pawlowsky (1906:156) 

 — a pupil of CholodkovskAr — of a resume of the literature up to his 

 time on the mouth parts of lice, and a description of the anatomy of the 

 piercing and sucking apparatus of the Pediculidae. 



Mjoberg (1910:203) made no studj^ of the mouth parts but confined 

 himself to a brief summary of the work of others, dealing at greatest 

 length with Enderlein's work on the hog louse and his interpretation 

 of the mandibles. Patton and Cragg (1913:531) gave an accoimt of 

 the mouth parts of Pediculus vestimenti " prepared, with the assistance 

 of the aljove papers [of Enderlein and Pawlowskj^], from sections and 

 dissections." This account included also a description of the first part 

 of the alimentary canal. The fact that the man-infesting pediculi are 

 an etiological factor in the transmission of certain diseases has led to the 

 publication within the last few j^cars of three detailed papers on the 

 anatomical structm'e of the anterior part of the almientarj^ canal and 

 of the mouth parts proper. Those of Harrison (1916b) and Sikora (1916) 

 appeared almost simultaneously, and that of Peacock (1918) some two 

 years later. Owing to war conditions the work of Sikora was not available 

 to the other two investigators, nor their work to her. Harrison and 

 Peacock confined their investigations to the species affecting man, while 

 Sikora introduced several species, among them the hog louse, for purposes 

 of comparative study. 



The head of the hog louse is most strongly chitinized on the lateral 

 regions, and the chitinization extends a little way beyond the borders of 

 both dorsal and ventral surfaces. The rcmaintler of the ventral surface 

 is only weakly chitinized, and at the anterior end the integument is 



