Abstract
The term ‘organule’ is proposed as an English equivalent for the German word ‘Kleinorgan’. The different organules on the third sternite of Oncopeltus are described: larvae possess innervated bristles and special sensilla termed ‘chemosensilla’, whereas the adult develops, in addition, a dense population of non-innervated hairs. The hairs, bristles and ‘chemosensilla’ each develop from mother cells which undergo a particular series of differentiative divisions. The course of events is described for each type of organule. Electron-microscopic studies of the fine structure of the outgrowing hairs are described. As in the outgrowth of a scale, longitudinal arrays of microtubules and bundles of fibres are found in the first cytoplasmic process of the trichogen cell. Experiments show that bristle determination occurs between the onset of the moult and the proliferative cell divisions in the epidermis. The period of hair determination is found to occur later than that of the bristles and to be later than the proliferative cell divisions in the last larval stage. A discussion of the results includes a review of the knowledge of differentiative divisions concerned in the formation of organules in other groups of insects, and a consideration of Wigglesworth's theory of bristle determination.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.