ˌdeləˈnisəs noun
Usage: capitalized
Etymology: New Latin, from bdell- + -nyssus (from Greek nyssein, nyttein to prick, sting) — more at numen
: a genus of mites (family Dermanyssidae) parasitic on vertebrates and including serious pests (as B. bursa and B. sylviarum ) of domestic fowl and the tropical rat mite