132 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



garded as rather definitely fixed, but within the last few years 

 evidence has been found which indicates that a readjustment 

 is again desirable. 



Handlirsch and Cholodkovsky have favored an arrange- 

 ment which restores the Anoplura and Mallophaga to a posi- 

 tion very similar to that which they originally held in relation 

 to each other, and other authors have brought forward evi- 

 dence in support of this view. As a result of a comparative 

 study of the two groups Mjoberg has concluded that they are 

 really quite closely related, the Anoplura being merely a further 

 adaptation to a parasitic life, and with this view Kellogg and 

 Cummings are inclined to agree. Enderlein alone, of recent 

 authors, has contended for retaining the Anoplura as a sub- 

 order of Hemiptera. The evidence is too voluminous to be 

 reviewed here, but it indicates very strongly that the Ano- 

 plura really have nothing to do with the Hemiptera and are 

 related to the Mallophaga. It seems best to regard the Ano- 

 plura as a distinct order and in the latest classification of the 

 Insecta, that of Brues and Melander, this is done. However, 

 the problem of their relationships is still an open question 

 which can only be settled by much more careful comparative 

 morphological studies. 



The classification within the order itself is extremely sim- 

 ple; too little is known about the group for the classification 

 to be otherwise. Four families, all of which apparently form 

 quite natural groups, are recognized. Of these, one, Haema- 

 tomyzidse, contains a single remarkable species (with a possi- 

 ble variety) which occurs upon elephants. Another small fam- 

 ily, Echinophthiriidse, is limited in its occurrence to marine 

 mammals, its peculiarities being ascribable to adaptation to 

 the aquatic life of the hosts. The Pediculidse include the spe- 

 cies found upon man, apes and monkeys, and the remainder 

 of the species are contained in the family Hsematopinidse. 



Nearly as many species have been described since 1908 as 

 had been described previous to that time, but in spite of this 

 activity the study of the group has hardly begun. The host 

 list, when compared with a list of the mammals of the world, 

 is pitifully small, as is instanced by the fact that there are but 

 four records of Anoplura from mammals of the South Ameri- 



