Development of the nervous system in the locust Locusta migratoria

Methylene blue vital staining was used to study anatomy of the nerve ventral cord and development of some elements of the peripheral and central nervous systems of first-fifth instar larvae of the locust Locusta migratoria migratorioides, The thoracic ganglia were shown to markedly increase in size during the third instar, which is probably connected with the rapid differentiation of body segments, wing development, and the appearance of flight motor activity. A heterochronia in the development of neurosecretory and motor neurons of the dorsal longitudinal muscles was found. The data obtained illustrate the systemic principle of neural control organization: they indicate clearly that individual subsystems of the nervous system develop nonuniformly.