Abstract
Current research on Dennanyssus is surveyed briefly. Phenetic similarities among the 16 known species are analyzed using techniques of numerical taxonomy, including principal component analysis and multidimensional scaling. Dermanyssus trochilinis, n. sp. is described from a hummingbird nest in Peru. D. faralloni and D. antillarum are re-illustrated. The species are keyed. The status of D. passerinus and D. longipes remains unsettled.