The morphology of juvenile instars of the oribatid mite, Siculobata (Paraleius) leontonycha (Berlese, 1910) is described and illustrated, based on material collected from the galleries of bark beetles, Ips typographus L. (Coleoptera, Curculionidae, Scolytinae) under the bark of Picea obovata in Western Siberia, Russia. Juveniles are characterized by folded gastronotum and anogenital region, well-developed, setiform, barbed prodorsal setae, clavate bothridial setae, 11 pairs of gastronotic setae in larva and 15 pairs in nymphs, all with excentrosclerites, thick or slightly broadened in median parts, erect, barbed (except setiform p1-p3 in protonymph), epimeral formulas 3-1-2-1 in protonymph, 3-1-2-2 in deutonymph and 3-1-3-2 in tritonymph, ontogeny of genital, aggenital, adanal anal setal formulas 0-1-2-3, 0-0-1-1, 0-0-3-3, 0-0-0-2, respectively. The morphological differences of ontogenetic instars for S. (Paraleius) leontonycha to known species of Scheloribatidae are given.