The Hog Louse 643 



In the same year Gross (1903 : 347) published the results of his investigation 

 of the ovaries of the Mallophaga and the Pediculidae. In his introduction 

 he sums up an earlier investigation as follows: 



Haudlirsch (1903) places them [the Pediculidae] in a special order Siphunculata, Meinert 

 next the Mallophaga in his subclass Blattaeformia. Borner (1904) gives iihem the same name, 

 but raises the family to the ranli of a suborder which, together with the Corrodentia, the Thy- 

 sanoptera, and the Rhynchota, forms his order of Acercaria. Cholodkovsky (1904) joins tlie 

 Pedicuhdie and the Mallophaga in one order, related with the Orthoptera rather than with 

 the Hemiptera, for which he proposes the name Pseudorhynchota. Finally, Enderlein (1904) 

 interprets the Pediculidae as one with the Anoplura — a name originating with Leach — 

 an order lying near to the Rhynchota. None of the four opinions mentioned is to be con- 

 sidered as entirely new. They are all found in similar form in the old entomologies of the 

 preceding century.- 



Gross next emphasizes the importance of using other less delicate organs 

 than the mouth parts as a basis for comparison. 



A historical review of lice from the time of Aristotle, together with an , 

 account of the general characteristics of the order and descriptions of 

 species, was prepared by Von Dalla Torre (1938) for the Genera Insectorum. 

 For this Enderlcin's work served as a basis, as it did also later for the 

 section on lice in the textbook of Patton and Cragg (1913 : 525) . Neumann 

 (1909:530) criticized Enderlein's splitting-up of the old genus Haematopi- 

 nus of Leach as being for the present uniecessarjr, and retained the 

 original classification in his descriptions of species (1911). Mjoberg (1910) 

 published comparative studies of Anoplura and Mallophaga dealing with 

 both the morphclogical and the systematic aspects of the question. Pre- 

 vious to this tmre only the dissertation of Strobelt (1882, EngKsh trans. 

 1883 : 73) had dealt with the anatomy of a species of Haematopinus — 

 H. tenuirostris, now Linognathus vituli. The observations of the earliest 

 workers- — Hooke(1665), Swammerdam (1G82), and Lecuwenhoek (1695) — 

 and the investigations of the scientists of the latter half of the nineteenth 

 century, dealt exclusively with the species infesting man. The presence 

 of great armies in the field during the five years from 1914 to 1918, inclusive, 

 compelled intensive studies of these species from medical and sanitary 

 standpoints, with the subsequent publication of many valuable papers, 

 of which a liberal use has been made in interpreting the anatomy of the 

 species under investigation. 



The classification followed throughout this paper is that suggested by 

 Nuttall (1919:329) in a recent review of the systematic hterature of the 



2 Translated from the original German. 



