The results of experimental rearing of Neotrombicula inopinata and Leptotrombidium russicum and of field studies aiming at finding the hitherto unknown habitats occupied by active postlarval forms are presented. Diagnoses of deutonymphs reared from field-collected larvae of both species are provided. Literature interpretation of deutonymph of N. inopinata is inconsistent with the characteristics of deutonymph of N. inopinata obtained from larvae by experimental rearing. Larvae of L. russicum and L. silvaticum can be separated only on the base of host spectrum. Considering the biology of the parasite and host species, it is likely that postlarval forms of bat-parasitizing species may be confined to tree and cave habitats, whereas those species that are known as parasites of rodents inhabit the soil habitats.