MANGE OF POULTRY 135 



thigh. Where many are present they cause irritation with the foi'ma- 

 tion of yellowish, oval nodules. These are about 0.5 mm. by 1 mm. 

 in dimensions, and a large number of them may cover a small area. They 

 are soft, granular or calcareous, and may contain the dead parasites. 

 The health of the host does not appear to be affected by the lesions 

 which these parasites produce. 



