1. The Apterous (ap) gene is required for the normal development of the wing and haltere imaginal discs in Drosophila melanogaster

2. The imaginal differentiation depends on thoracic factors. Derangements in the 2-hormon-system lead to the formation of premature adultoids.

3. In Drosophila, the gene Apterous (ap) divides the wing imaginal disc in dorsal vs ventral cell lineages and is required for wing formation

4. (P.) walkerae, which were carried out under constant abiotic and biotic conditions, revealed distinct quantitative and species-dependent differences in the sucking behaviour of larvae, the moulting period of larvae and nymphs, and in the necessary number of postlarval stages for the development of adult ticks, as well as differences in the duration of the imaginal metamorphosis and the species-typical temporal and quantitative features for oviposition.