DEVELOPMENT AND HISTOLYSIS OF INDIRECT FLIGHT MUSCLES IN DYSDERCUS INTERMEDIUS

The dorsal longitudinal muscle of Dysdercus intermedius (a 'cotton stainer') develops from a precursor muscle which in early instars consists of small fibres, nuclei, and myoblasts. Growth of the muscle occurs by the incorporation of myoblasts and differentiation of their cytoplasm into fibrils and sarcosomes. Fibre cleavage was not observed. Development is not complete until the third day following the final ecdysis, when the myofilaments become organized into a typical hexagonal pattern. Degeneration of the indirect flight muscles occurs in all adult females, and it coincides with oöcyte growth; it also occurs in a few senile males. Histolysis involves the breakdown of muscle fibrils and release of droplets into the haemocoel. When complete, only sarcolemma, nuclei, and tracheae remain. © 1969.