CHAPTER XI 



MITES AND TICKS 



On account of their economic and medical importance the order 

 Acari which comprises the mites and ticks has attracted more 

 attention than all the other Arachnida put together. Because of 

 their vast numbers, small size and the enormous taxonomic diffi- 

 culties involved, their study is very much a matter for the special- 



FiG. 39. Examples of various kinds of mites: 1. Notostigmata, 

 2. Dermanyssidae, 3. Halarachnidae, 4. Ixodid tick, 5. Argasid 

 tick, 6. Demodicidae, 7. Bdellidae, 8. Halacaridae, 9. Hydrach- 

 nidae, 10 Thrombidiidae, 11. Tyroglyphidae, 12. Sarcoptidae, 

 13. Oribatei, 14. Eriophyidae. (From various sources.) 

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