The morphological ontogeny of Heptacarus hirsutus Wallwork, 1964 is described and illustrated. All instars of this species have two pairs of exobothridial setae, which is characteristic for the lower Oribatida. They have strong chelicerae, anal opening in a posteroventral position, and thick legs I and II, features which are typical for xylophagous mites. The larva has 34 gastronotal setae, including inguinal h₄, a striking feature of the lower Oribatida, this stage has also a long, cudgel-shaped Claparède's organ. In the next instars of H. hirsutus, a strong hypertrichy occurs on the posterior part of the hysterosoma, and the number of setae increases in the protonymph, deutonymph, tritonymph and adult to about 60, 75, 95 and 115 setae, respectively. In the deutonymph, tritonymph and adult of H. hirsutus, the ano-adanal plate is incompletely fussed.