[Histo-cytological features of distal processes concerning the 2 vasopressin-neuropysin-like cells of the migratory locust (author's transl)].

Distal processes of 2 "vasopressin-neurophysin-like" cells are described in the migratory locust. These projection fibers are studied at the level of the thoracic somatic nerves, brain and optic lobes. In the thoracic nerves, projections find their way along non-neurosecretory axons (Fig. 5). They end in swellings under the nerve sheath (Fig. 8). Those swellings show that cord somatic nerves could represent a new releasing site of neurosecretion in insects. At brain level, projections branch towards the optic lobes and end in 2 protocerebral commissures, one of these being the optic commissure (Fig. 1 and 2). In the optic lobes, projections run dorsally and ventrally along the neuropile structures without going inside (Fig. 1). The most important ones end in small swellings (Fig. 3 and 7) near neurosecretory perikarya found among lamina interneurons (Fig. 4 and 6). Brain and optic lobe projections are presumed to receive information from the environment outside by means of the lamina neurosecretory cells. A modulatory action of these projections over the lamina neurosecretory cells and/or over other adjoining neurons has also been considered.