First description of the nymph and larva of Dermacentor compactus Neumann, 1901 (Acari: Ixodidae), parasites of squirrels (Rodentia: Sciuridae) in southeast Asia.

Recent reexamination of collection lots stored in the United States National Tick Collection revealed adult specimens of Dermacentor compactus Neumann, 1901 (Acari: Ixodidae) reared from field-collected nymphs, which allowed us to associate field-collected unidentified nymphs and larvae with this species. Nymphs of D. compactus can be easily distinguished from those of other congeneric species by the shape of the scutum and spiracular plate, the hypostome dentition, and the size of the spurs on the coxae. Larvae of this species can be distinguished by the shape and sculpture of the scutum, the shape of basis capituli, the absence of auriculae, and the size of the spurs on coxae II and III. Both nymphs and larvae feed mostly on various species of squirrels (Rodentia: Sciuridae). Considerably fewer nymphs and larvae were found on murid rodents (Rodentia: Muridae), domestic dogs (Carnivora: Canidae), and a snake (Squamata: Colubridae).