The Histology of the Neurosecretory System of the Adult Female Desert Locust, Schistocerca gregaria

The pars intercerebralis of the brain of the desert locust contains about 2,400 cells in two groups, which stain with chrome-haematoxylin-phloxin and with paraldehydefuchsin. On the basis of differences in size and staining reactions, four types of cell, called A-, B-, C-, and D-cells may be differentiated. The Aand B-cells produce different kinds of material; they are not thought to be stages in a secretory cycle. The Cand D-cells are probably not neurosecretory. The corpora cardiaca are divided into two regions. One part stores neurosecretory material from the pars intercerebralis and the other is glandular in appearance. Material discharged from the Aand B-cells in the immature female passes along the nervi corporis cardiaci I to the anterior parts of the corpora cardiaca. The mature female is characterized by the presence of very much larger amounts of material in the corpora cardiaca, in the nervi corporis cardiaci I, and in the A-cells of the pars intercerebralis. The significance of this larger amount of material with respect to neurosecretory cell activity is discussed.