ANOPLURA. 



661 



nearly. These creatures live on the younger and more 

 succulent portion of the feathers of birds and possibly on 

 the hairs and epidermal scales of mammals, and are said to 

 use their anterior legs in feeding. There is as a rule a certain 

 relationship between the species of the biting-lice and the species 

 of its host, but certain birds are infested by more than one 

 species, e.g. the common fowl has five. They often die soon after 

 their host. There are about a thousand species recorded. 

 Howard recognizes four families : 



Fam. 1. Triehodectidae. Antennae filiform with three joints ; no 

 labial palps ; tarsi with a single claw ; infest mammals. Trichodectea 

 latus is the biting-louse of the dog. T. sphaerocephalus is one of the 

 common sheep parasites in England. 



Fam. 2. Philopteridae. Antennae five-segmented ; no labial palps ; 

 tarsi with two claws ; infest birds, Nirmus, Goniodes. 



Fam. 3. Gyropidae. Antennae clubbed with four segments ; tarsi 

 with one claw ; found on mammals. Gyropus. 



Fam. 4. Liotheidae. Antennae clubbed with four segments ; tarsi 

 with two claws ; infest birds. Tetrophthalmus. 



Order 4. ANOPLURA.* 



Small, thin-skinned insects ; wingless ; head bears a tube ending 

 in hooks for attachment, within this is a portrusible sucking tube ; 

 thorax indistinctly 

 segmented ; legs end 

 in a single claw. 



Lice are parasitic 

 on Mammals on 

 whose blood they 

 live. In spite of 

 the fact that three 

 species infest man 

 we are curiously 

 ignorant of many 

 features of their life 

 history and of their 

 structure. 



The tube by which they attach themselves to the skin is usually 

 homologized with the labium whilst the inside tube is looked 

 upon as the equivalent of the combined mandibles and maxillae. 



* E. Piaget, Les Pediculines, Leyden, 1880-85. 



FIG. 415. Phthirius inguinalis (after Landois). St stigma 

 Tr trachea. 



