Quarterly Journal of Microscopical Science, Vol s3-100, 51-64, Copyright © 1959 by Company of Biologists

The Prothoracic Glands of some Coleopteran Larvae

¹ Department of Zoology, Imperial College, London, S.W. 7; Department of Zoology, University of Allahabad, India

The paired prothoracic glands of the larvae of 15 species of Coleoptera have been described. Each is a syncytial or cellular band attached at its ends to the dorsal and ventral tracheal trunks running from the prothoracic spiracles to the head, or the branches of these trunks; the gland may be spread over one or both of the tracheal trunks to a varying degree, shows no nuclear divisions during postembryonic development, and has no nerve-supply. There seems to be a tendency for the glands to be more anteriorly placed in the primitive groups and more posteriorly placed in the specialized ones. No relationship seems to exist between the morphological and histological nature of the gland and the taxonomic position of the insect, nor is there any proportionality between the size of the gland or its nuclei and the size of the insect. But there seems to be a direct relation between the volume of the whole gland and its total nuclear volume, and an inverse relation between the number of nuclei in the gland and the size of the individual nuclei.