i 4 THE SCOTTISH NATURALIST 



Ferris's introductory remarks are of interest as indicating 

 what progress has been made in the study of the Anoplura 

 within comparatively few years. Previous to 1904 most of 

 the species were included in the genus Hcsmatopiniis, and 

 only one family was recognised. Now there are twenty-three 

 genera, arranged in four families. The systematic position 

 of the whole group has also been changed. Formerly they 

 were treated as a sub-order of Hemiptera, but there is now 

 every reason to believe that they are related to the Mallo- 

 phaga or Bird-lice, and that they should, provisionally at 

 least, be regarded as constituting a distinct order. The 

 distribution of the Anoplura among their various hosts is 

 strongly reminiscent of what occurs in the Mallophaga, for 

 " the remarkable degree to which these parasites are broken 

 up into natural groups that are strictly confined to closely 

 related groups of hosts, is now clearly evident, while previously 

 it was barely hinted at. The problem of their distribution is 

 shown to be almost exclusively the problem of the genetic 

 relationships of their hosts." Of the four families recognised 

 one (Haematomyzidae) contains only a single species confined 

 to elephants ; a second (Echinophthiriidae) comprises forms 

 which are found only on marine mammals ; the third (Pedi- 

 culidae) includes the species which infest man, apes, and 

 monkeys ; while all the remaining forms are contained in 

 the fourth family (Haematopinidae). 



The following key (adapted from that of Ferris) may 

 assist in the determination of our British genera: 



1. Body thickly beset with more or less short, stout spines, or 



with spines and scales. Occurring exclusively on marine 



mammals. Fam. Echinophthiriid.*: . . 2 



Body with spines or hairs always in definite rows, never 



with scales. Occurring exclusively on land mammals 3 



2. Thorax and abdomen bearing delicate scales. Antennas 



five-segmented . Subfam. Antarctophthiriin^e. 



Genus An ta rctoph th irius 

 Thorax and abdomen without scales. Antennas four-seg- 

 mented . . Subfam. Echinophthiriin^:. 



Genus Echinophthirius 



