Abstract
Transection of ventral nerve cords and implantation of ganglia were performed in crowded Leucania separata larvae which were destined to become black in body colour. Transection of the oesophageal connectives at 21 hr before the 5th-larval ecdysis resulted in pale coloration in the 6th-instar larvae. Implantation of suboesophageal ganglia taken from larvae before the 5th-larval ecdysis into isolatted abdomens resulted in more intensive melanization than implantation of those from the 6th-instar larvae soon after ecdysis. The ganglia taken from the 6th-instar larvae, of which oesophageal connectives had been transected at 21 hr before 5th-larval ecdysis, resulted in intense melanization after implantation into isolated abdomens. It is suggested that during the larval moulting some stimulation transmitted posteriorly through oesophageal connectives promotes release of the hormone(s), which cause(s) melanization, from the suboesophageal ganglion.
