THE PROTHORACIC. GLANDS OF LEUCOPHAEA MADERAE (ORTHOPTERA)

¹ Department of Anatomy, University of Colorado Medical Center

1. The prothoracic glands of Leucophaea maderae are paired band-like structures located in close proximity to and innervated by the prothoracic ganglion. The longitudinal axis contains striated musculature, a nerve and a trachea. The glands are well developed in nymphal stages, but regress in the imago.

2. In the nymph the glandular tissue consists of layers of dense nuclei surrounded by scanty cytoplasm. In their histological appearance the prothoracic glands strikingly resemble the corpora allata of the same species. The nymphal prothoracic glands exhibit a cyclic nuclear activity, characterized by a spurt of mitotic divisions during the intermolt period and by quiescent phases preceding and following each molt.

3. In freshly emerged male and female adults the prothoracic glands are still nymphal in appearance. Involution takes place during the first week of the adult stage. It manifests itself by a breakdown of nuclei and results in a reduction of the tissue bands to practically nothing except the muscular core.

4. The prothoracic glands of Leucophaea are considered to be homologous with the prothoracic glands of Lepidoptera and Hymenoptera, with the "ventral glands" of lower Pterygota, with the "intersegmental organs" of Odonata, and possibly with the "parenchymatous tracheal organs" of Hemiptera. They have certain features in common with the thymus of the vertebrates.