The Bird-Lice 



they always have a sufficient supply of air even when the bird or 

 a portion of its body remains under the water for some time. 



It is very rare that bird-lice ever leave the. body of the host, 

 but they do migrate from one bird to another whenever two birds 

 come in contact, as during the nesting season or among birds of 

 gregarious habits. 



In many cases a given species of Mallophaga will be found 

 to be confined to a given species of bird or mammal, but in other 

 cases one species of parasite will be 

 found upon two or more species of 

 birds. Curiously enough, some of these 

 parasites are found in Europe on birds 

 which differ from those upon which 

 identically the same species of parasite 

 is found in North America. Several 

 species may occur upon the same bird; 

 for example, at least five species be- 

 longing to three distinct genera have 

 been found upon the common fowl. 

 Nearly all of these are cosmopolitan in- 

 sects and have been carried upon fowls 

 to all parts of the world. Chickens 

 hatched in an incubator should be 

 absolutely free from lice and remain so 

 until they join company with older fowls, 

 that the habit which hens have of bathing themselves in dust 

 is an effort on their part to get rid of the irritation caused by 

 these creatures. 



TABLE OF FAMILIES 



Antennae filiform with three or five joints; no labial palpi. . i 

 Antennae clubbed or knobbed and with four joints ; four-jointed 



labial palpi 2 



i Antennae three-jointed; tarsi with one claw; found on mam- 

 mals Family Trichodectidce 



Antennae five-jointed ; tarsi with two claws; found on birds 



Family Philopteridce 



2 Tarsi with one claw; found on mammals. . .Family Gyropidce 



Tarsi with two claws; found on birds Family Liotheidce 



Any detailed consideration of the habits of these families 

 will be unnecessary, as they do not differ in a sufficiently marked 

 manner to necessitate such treatment. 



349 



Fig. 239. Goniocotes 



dissimilis. 

 (After Denny.) 



There is little doubt 



