SECTION III 



EXTERNAL PARASITES 



More than thirty species of external parasites infest l)irds: 

 their economic importance is very great; fowls heavily in- 

 fested with an}^ of them are unprofital)le, and many of these 

 parasites are so injurious as to kill the infested birds. 



It is necessary to know something of the life history of 

 these parasites and their habits to intelligently combat their 

 parasitisms. This information is given as briefly as possible 

 in the following pages : 



The external parasites affecting birds consist of lice, whicli 

 infest all ages and breeds; scah parasites, producing scaly 

 legs; the air sac mite, which is a modified scab parasite and 

 infests the air sacs; the cliigger (chigger or jigger) or red 

 mite, a great pest in the hot summer months ; a distinct bird 

 fiea; the chicken hug, which in many respects resembles the 

 common bedbug, and the ring worm. In all, seven different 

 classes. 



LICE OF BIRDS 



This embraces a group of biting lice ; their bodies are flat 

 and their mouth parts are arranged for biting and cutting. 

 They live upon feathers, epidermis and secretions of the 

 body of their host. As may be noted in Fig. 19, the mouth 

 parts are located just back of the antenna and are not al- 

 ways" visible. The antennae consist of five articles or joints 

 each. The thorax in some species is long and narrow, 'n\ 

 others short and globular. They are provided with three 

 pairs of legs which are attached to the thorax. The free 

 extremity of the legs is provided with two booklets or claws 

 which enable them to hold on to their host. The body and 

 legs may be covered with a greater or less quantity of hair 

 or bristles. 



The lice of birds are placed under the following genera: 

 Menopon, Goniodes, Goniocotes, Lipeurus, Docophorus and 

 Nirmus. 



Menopon hiseriatum Cthe large chicken louse). — This is the larg- 

 est louse found upon chickens. It is about one-twelfth of an inch in 

 length. It is light in color. Fig. 19 illustrates this louse much 

 enlarged; the short mark at the right shows the actual length of 

 this louse. This parasite is common on the heads of young chickens. 



Menopon pallidum (the small chicken louse). — This louse is illus- 



