The most striking fact revealed by investigations of insect neurohormones is that insects are as well supplied with neurohormones as mammals, since neurohor mones regulate not only the functioning of the endocrine glands, prothoracic gland, and corpora allata, but also most physiological processes. Our knowledge of neurohormones developed originally from anat omocytological investigations and experimental studies. Today, accurate bio assays have been devised for studying both in vivo and in vitro physiological processes, and RIA determination has yielded knowledge of titer modifications of...