From ZooTerms (Dictionary of Invertebrate Zoology)
Arthropoda: Chelicerata) Any surface or anatomical feature, enclosed or not, internal or external, that regularly serves as an abode for mites.acarinarium (noun; plural acarinaria; Greek akari, mite or tick; Latin -arium, place for): 1. (
2. (Arthropoda: Insecta) In Hymenoptera, variously placed and constructed integumental cavities that serve as abodes for mites in certain eumenine wasps; originally defined as the enclosed acarid chambers of xylocopid bees.