110 ACAEINA OE MITES. 



partial parasites, the hen mite is nocturnal, hiding away in 

 crevices of the walls, &c., during the day-time. Sometimes they 

 even attack the nasal cavities of the birds, and also other 

 animals to which they may become transmitted.^ 



Family Ixodidse. — The members of this family are popularly 

 called Ticks. Ixodidse are large Acari with a tough leathery 

 skin, the front of the body covered with a hard protecting shield. 

 All the ticks are blood-suckers, living some part of their life 

 upon other animals, usually warm-blooded vertebrates and birds. 

 A very formidable mouth is present, composed of mandibles and 

 a sharp piercing rostrum, which is made up of two lateral parts 

 and a central part with recurved barbs at the tip. When a tick 

 is fixed on an animal it is impossible to pull it off: the soft 

 body comes away from the head,- which is held firmly fixed by 

 the barbs in the host's flesh. The hind part of the body is 

 capable of very considerable distension, although tough. Ticks 

 are found amongst grass, shrubs, and especially on sandy soil. 

 When on the soil they are quite small creatures, but very active. 

 They crawl about over the grass and vegetation, and eventually 

 get fixed on to some passing mammal or bird, from which they 

 instantly commence to suck blood. During this temporary 

 parasitism the body swells enormously, owing to the quantity 

 of blood taken in. When the tick has completed its meal it 

 falls from the host to the ground again, and may remain for 

 some weeks without any food. This habit seems only charac- 

 teristic of the females. The males are small, and non-para- 

 sitic upon warm-blooded animals. They most likely feed on 

 invertebrate blood, as we see in the male Jigger (one of the 

 Fleas). The small males remain attached to the females for 

 som,e days. The ova are laid by the ticks on the ground 

 where the fully gorged adult has fallen off. The Sheep Tick 

 {Ixodes reduvius) and the Ox Tick (7. reticulatvs) are frequently 

 very annoying and injurious to the health of those and other 

 animals. They are often the indirect cause of serious maladies, 



1 The Parasitic Diseases of Poultry, p. 52. F. V. Theobald. 1897. 



