title: The cerebral neurosecretory cells of cicadas (Homoptera: Cicadidae).
abstract: The cerebral neurosecretory cells (NSCs) of three cicadid species (Tibicen plebeja Scop., Cicada orni L. and Melampsalta musiva (Germ.) were studied in sections stained with PTh-PF, AB-PF and PThPh. There were revealed numerous scattered NSCs of the cellular cortex, three paired groups (M 1, M 2, M 3) of the median NSCs homologous to the corresponding NSC groups of Holometabola, and lateral NSCs not forming a single compact group. The group MI located in the pars intercerebralis was found to consist at least of four NSC types in Tibicen plebeja and in Cicada orni and of six NSC types in Melampsalta musiva. Four cells of two groups M 2 were observed at the basis of MI-group, and four NSCs of two M 3-groups - in the anterior cellular cortex of the protocerebrum. The nerve fibers of M 1-group NSCs send out side branches lateralwards into the dorsal protocerebral neuropile, then they cross with their contralateral counterparts and leave the brain within the nervus corporis cardiaci I. The M 2- and M 3-cell fibers do not join those of MI-group NSCs. The M 2-cell fibers could not be traced for a long distance, whereas M3-cell fibers were observed to pass apparently into the circumoesophageal connectives. The cerebral neurosecretory system of Cicadidae seems to be similar in its organization level to that of Neuroptera and is considered as less advanced that that of Geocorisae (Heteroptera).
mesh_terms: D000818:Animals; D001369:Axons / Q000648:ultrastructure; D001921:Brain / Q000033:anatomy & histology*; D007313:Insecta / Q000033:anatomy & histology*; D009412:Nerve Fibers / Q000648:ultrastructure; D009434:Neural Pathways / Q000033:anatomy & histology; D009474:Neurons / Q000648:ultrastructure; D009490:Neurosecretory Systems / Q000033:anatomy & histology*