MITES 



537 



MITES 



The mites belong to the Acarina, an order included in the 

 class Arachnida, and are related to the scorpions, spiders, 

 cattle ticks, etc. Some species are parasitic upon animals, 

 others upon plants. The latter are included in the group 

 Eriophyidae, all the members of which are very minute, 

 ranging between ^i^ and - of an inch in length, hence they 

 are hardly visible to the naked eye. The mites are almost 

 colourless, worm-shaped, and composed of two distinct parts. 







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Fig. 162. Left-hand fig., Eriophyes ribis, the black currant bud 

 mite. Middle fig., Eriophyes vitis, thevine leaf mite. Right-hand 

 fig., Eriophyes avellanae, the hazel bud mite. All highly mag. 



The anterior part is broad and short, and consists of the head 

 and thorax fused together, constituting the cephalo thorax ; 

 the posterior portion or abdomen is elongated and tapering, 

 and delicately transversely striated. Two pairs of legs are 

 borne close to the rostrum. 



In addition to the species of economic importance, many 

 mites form galls on our wild plants. 



Black currant gall mite. This disease of black currants, 



