138 



POULTRY disease;s and the;ir tre;atment. 



stages the disease does not appear to disturb the general health 

 of the fowl. As it progresses the birds become lame and some- 

 times the foot becomes so badly diseased that joints or even 

 whole toes drop off. The photograph of a badly affected leg 

 is shown in fig. 30. The two legs are usually affected equally. 



JJ^^ 



j^- 



Fig. 31. Photograph of the adult female of the mite Knernidocoptes 

 (DeniiatorycfesJ miifans. (After Haiduk). 



Etiology. — The disease is caused by the minute parasitic mite 

 Knernidocoptes mittans (figs. 31 and 32). 



