38 MITE PARASITES. 



III. MITE PARASITES. 



At least eighteen species of Mites are found para- 

 sitic on the Fowl. Four only of these can be said to 

 be truly injurious, although the remaining fourteen 

 now and then are sufficiently abundant to be pre- 

 judicial to the host's health. Mites are distinct from 

 Insects, They are included in the group J carina, 

 and are more closely related to the Spiders than to 

 the Insects. 



These Acarina are characterized by a number of 

 distinctive features, chief amongst which is the usual 

 presence of four pairs of legs. They are generally 

 small and thick, and have the head, thorax, and 

 abdomen all united into one piece. The six, five, 

 or even three-jointed legs terminate in hairs, claws, 

 and in some in a curious sac-like vesicle, useful 

 for the minute creature to hold on by to its host, for 

 nearly all mites are parasitic. 



The permanent parasitic mites with which we are 

 interested in this article breathe not through stigmata, 

 but their respiration is cutaneous ; their skin alone is 

 the respiratory apparatus. Other mites have true 

 stigmata. The sexes are separate in all the mites. 

 The males are always few in number and much 

 smaller than the females ; they also often lead quite 

 a different life to the females. Mites undergo a 

 kind of incomplete metamorphosis. The eggs or 

 nits laid by the female hatch into little six-legged 



