March 1896.] PAEASITES OF POULTRY. 423 



Fig. 4. 



Fowl louse (Lipeurus variabilis^ (greatly enlarged). 



nine months upon fresh feathers, the quill epidermis being 

 especially eaten. Before reaching the full-grown state as many 

 as ten to twelve moults apparently take place, there being little 

 difference in each stage, except the gradual darkening of the 

 markings. 



(8.) Mites {Acari, Acariases, Dermanysses). — Mites are very 

 minute creatures, and are not true insects, having four pairs of 

 legs. Some are partial parasites, living on the birds at night, 

 as Dermanyssus gallince (Fig. 5), the commonest fowl mite; 



Fig. 5. 



Dermanyssus gallince and ovum (greatly enlarged). 



others are permanent parasites, as Sarcoptes, living at the base 

 of the feathers, and popularly called " Depluming scabies " (Fig. 6). 

 Others, again, live under the skin, forming scabby growths, such 

 as are seen on fowls' legs (Sarcoptes mutans). These are armed 

 with a pricking mouth, with which they torment the birds, 

 especially at night, causing loss of condition, hindering setting, 

 and creating loss in other ways. 



The most injurious form is the red or common fowl mite. 



The Fowl Mite (Dermanyssus avium or gallince). — This very 

 minute creature is yellowish white to dark red in colour, 

 according to the amount of blood it contains, drawn from the 

 birds. They are found in abundance in pigeon-houses, poultry- 

 runs, and roosts. Both sexes are armed with a sharp rostrum ; 

 the female is most bloodthirsty. They feed upon the birds only 

 at night, and hide away in cracks and crevices in the nests, 

 perches, floors, walls, and ceilings during the day. Numerous 

 colonies can be found in the nests free and coupled together, 

 with countless eggs and quantities of exuviae and young forms, 

 especially in straw nests. They are most prolific, and can remain 

 for months without any food ; hence the removal of the birds 

 from the runs is useless a^s a remedy. The ova hatch rapidly. 



