Observations on the ontogeny of setae in the family Phytoseiidae (Acarina: Gamasina)

The ontogenetic development of setae on the dorsum and venter of the idiosoma and on the legs is described for the following four species of Phytoseiidae: Amblyseius andersoni (Chant). Amblyseius degenerans (Berlese), Phytoseiulus persimilis Athias-Henriot, and Typhlodromus pyri Scheuten. Homologous setal relationships between successive instars are discussed. The larvae of additional species were examined to determine if there are consistent patterns of setal development in the Phytoseiidae. A standard system of nomenclature for the setae on the idiosoma is applied to the immature instars.