MITES AND TICKS. 



373 



cants, causing "mange" in dogs. Follicle-mite (Demodex 

 jollictiloruiri}> common in the hair follicles of man and domestic 

 animals (Fig. 195). Gall-mites (Phytoptids), forming dimples 

 and pouches on plants. 



(b) With trachese. Harvest - mites ( Trombidium), whose minute 

 hexapod larvae are troublesome parasites in summer on 



FIG. 195. Follicle-mite 

 (greatly enlarged). 



FlG. 196. Itch-mite (Sarcoptes scabiei) 

 (greatly enlarged). 



insects, many mammals, and man. The so-called " red 

 spider" (Tetranychus telearius] spins webs, and lives 

 socially under leaves. Water-mites, e.g. Hydrachna on 

 water-beetles, and Atax on gills of fresh-water mussels. 

 Beetle-mites (Gamasus), often found on carrion beetles. 

 There is a common red mite on the shore-rocks, known as 

 Molgus (Bdella) littoralis. 



Ticks (Ixodidae, etc.) are the largest Acarina. They show a movable 

 " capitulum " bearing serrated cutting chelicerse and strong four-jointed 

 pedipalps. They are responsible for spreading the germs of some 

 diseases affecting man and beast, e.g. human " tick-fever " on the 



