MALLOPHAGA 



349 



in a state of nature they are very rarely an annoyance to their 

 hosts. The majority of the known species live on birds ; the 

 forms that frequent mammals are less varied and have been less 

 studied ; most of them have only one claw to the feet (Fig. 220), 

 while the greater portion of the avicolous species have two 

 claws. 



FIG. 219. Lipeurus ternatus, male ; 

 inhabits Sarcorkamphus po.pa. 

 (After Giebel.) 



FIG. 220. Trichodectes latus, male ; 

 inhabits the dog, Canis famili- 



Most of the forms have the anterior legs small, and they are 

 usually drawn towards the mouth, owing, it is believed, to their 

 being used after the manner of hands to bring the food to the 

 mouth; hence in some of our figures (219, 220) the body looks 

 as if it had only four legs. 



Very diverse statements have been made as to whether allied 

 forms of Mallophaga are found only on allied birds. It would 

 appear that this is the case only to a limited extent, as certain 

 species are found on quite a variety of birds ; moreover, some 

 birds harbour several species of bird-lice, even five genera having 

 been found, it is said, on one species of bird. Docophorus 

 icterodes has been recorded as occurring on many kinds of ducks 

 and geese ; the swan, however, harbours a distinct species, Doco- 

 phorus cygni, and this is said to have also been found on the 

 bean-goose. 



At least five species, belonging to three distinct genera, have 

 been found on the common fowl. The parasite most frequently 

 met with on this valuable creature is Menopon pallidum (Fig. 



