EXTERNAL PARASITES 47 



is also effective. These solutions should be used 

 warm. 



Premises. — For the eradication of scab para- 

 sites from infested premises, follow the directions 

 given for ridding premises of lice. (See page 40.) 



Air Sac Disease 



This is a very serious malady of birds that is 

 fortunately rather rare in this country; it is ex- 

 ceedingly difficult to eradicate once it has become 

 established in a flock. It is due to a scab parasite 

 called Cyiodites nudiis, synomnns for which are: 

 cytoleichus sarcoptides, Cnemidocoptes mutans, 

 and air-sac mite. 



Cytodites Nudus 



Description. — The body of this parasite is ovoid in shape, 

 as illustrated in Fig. 12. It is whitish in color and is pro- 

 vided with conical-shaped mouth parts, through which it sucks 

 fluids from the parts infested. The legs are rather short, 

 conical, and in both male and female all are provided with 

 suckers, which aid in moving about and in holding on. The 

 legs are composed of five articles (segments or joints) each. 

 The larva has three pairs of legs and the adult four pairs. 



Life History. — The ovigerous female lays eggs, as a rule, 

 but at times has been observed to deposit eggs ready to hatch 

 and even young larvae. The larvae pass through changes 

 similar to those of the scaly-leg mite by moulting several 

 times, and finally reaching the adult or sexually developed 

 stage. 



Symptoms. — The air sac mite inhabits the ab- 

 dominal air sacs, the air spaces of bones, and the 

 air cells (alveoli) of the lungs of chickens and 

 pigeons. If only a few parasites are present no 

 symptoms may be noticeable, but if they exist in 

 large numbers their effects may be serious. The 

 ])ird will become thin in flesh and even emaciated, 

 will appear dull, stay apart from the others of the 

 flock, and the comb will usually be pale in color. 

 The wings will droop and there will be labored 



