Formation of Central Nervous System in a springtail, Tomocerus ishibashii (Collembola: Tomoceridae) I

Abstract

Formation of the central nervous system is described. Protocerebrum consists of three pairs of ganglia (Lobes 1-3). Deutocerebrum is derived from the antennal, and the tritocerebrum from the intercalary ganglia. The lobe 3 of the protocerebrum is regarded as the ganglion of the preantennal segment. The tritocerebrum retains the original postoral position throughout the life cycle. The ventral nerve cord consists of ten pairs of ganglia deriving from the mandibular to the fourth abdominal segments. The metathoracic and four abdominal ganglia fuse to form a synganglion during embryogenesis.