We describe all stages of a new species of Tuckerella (Tuckerellidae) and offer proof of the existence of the tritonymphal stage within the family. Individuals of T. revelata sp. nov. were found inhabiting living insect galls formed on seed pods of Acacia burrowii (Mimosaceae) in Queensland, Australia. Based on the relative positions of the setae in the d series and e series, we suggest the presence of 6 setae in the d series (instead of 5) and 3 setae in the e series (instead of 4). The setae inserted in a caudal row on the dorsum of all post larval stages are inserted in a very different pattern in the larva. Only setae h2, h4, h5, h7 are inserted on a narrow dorsal shield along the posterior margin of the body, whereas setae hl, h3, h6, h8 are inserted on the venter in a transverse row posterior to the anus. During the first moult from larva to protonymph, seta h8 changes from leaf like to flagellate, and seta h3 changes from flagellate to leaf like. Our analysis of the addition of leg setae and the setae in the genital region supported the hypothesis of three post larval developmental stages. An alternative hypothesis of sexually dimorphic deutonymphs that the stage currently recognised as the tritonymph is the female deutonymph, and the stage currently recognised as the deutonymph is the male deutonymph, is not supported by our data.