BIRD AND BITING LICE 



fifty species of these insects on the British Hst, but will 

 heave a sigh of relief when told that, if cleanliness is 

 established, he is not likely to be brought into too in- 

 timate terms of acquaintance with any of them ! As 

 with the Aptera, these wingless insects (Fig. 4) are of 



Fig. 4, Dog Louse. (Enlarged thirty-six times.) 



small proportions, having a flat, hairy body, with a large 

 free head. The powerful mandibles with which the 

 obnoxious little " beast " is armed, are situate in a 

 cavity underneath the head, and the legs are attached 

 to the sides of the body-segments. There may be one, 

 or even two claws, on the extremity of the two-jointed 

 legs. The species shown in Fig. 4 is Trichodectes latiis 

 (Dog Louse). Fortunately for human beings the greater 



15 



