ArachnidayoudaoicibaDictYouDict[Arachnida 词源字典]
"A class of chelicerate arthropods that includes spiders, scorpions, mites, and ticks. They have become adapted for a terrestrial life and possess both lungs and tracheae, and many have silk or poison glands", Modern Latin (plural), from Greek arakhnē 'spider'.[Arachnida etymology, Arachnida origin, 英语词源]