Cleavage in Cheyletus eruditus (Acarina)

Abstract

IN his work on the embryology of the thelytokously parthenogenetic mite, Cheyletus eruditus, Hafiz¹ states: “The single nucleus of the ovum rises to the surface of the yolk and by dividing gives rise to a single layer of cells forming the blastoderm”. He also states that just before oviposition 4–7 small nuclei may be found entering the cortical layer of cytoplasm and that blastoderm formation is completed 2 hr. after deposition. Thus he ascribes to this mite a form of superficial cleavage which is already proceeding at the time of oviposition, a view not confirmed by my observations.