214 



Diseases of Poultry 



under the skin, causing deep-seated skin diseases like scaly- 

 leg; still others find their way into the internal regions of 

 the body, living either on mucous membrances like the air-sac 

 mite (p. 180) or upon the connective tissue like the connec- 

 tive tissue mite. 



The most common and most injurious mite parasitic on 

 fowls is the common fowl mite or red mite, Dermanyssus 

 galliiKB. These mites are present in almost every poultry 

 house that is not kept very clean. When they are present 



Fig. 40.- 



- The common "red mite'' of poultry, Dermanyssus gailinoe. 

 adult, d and e, young. (After Osborn.) 



in large numbers they are a serious pest. This mite is a 

 little more than | millimeter long. The female is a little 

 larger than the male. When empty they are gray with 

 dark spots, but usually they appear some shade from yellow 

 to dark red according to the amount of fowl's blood they 

 contain. They visit the fowls only to feed and spend the 

 rest of the time on the under sides of the roosts, in cracks 

 and crevices, under collections of droppings or other filth 

 and in the nesting material, especially if such material is 

 dirty straw. The mites breed in these places. They repro- 



