The patterns of localization of neurons reacting with antisera railed against two neuropeptides, locustatachykinin I (LomTK I) and leucokinin I (LK I), were investigated in the brain and retrocerebral complex (corpora cardiaca- corpora allata; CC - CA) of the last instar larva from the wax moth, Galleria mellonella. About 46 LomTK I-immunoreactive (LomTK I-IR) neurons are distributed through the brain. Most of the medial neurosecretory cells show axonal deccussation in median protocerebrum before contrlateral projection into the retrocerebral complex. This result is remarkably different from those described in various insects studied so far. Some nerve fibers from LomTK I-IR neurons are innervated to both CC and CA. A part of the LomTk I-IR nerve fibers run into the ventral nerve cord. About 14 LK I-immunoreactive (LK I-IR) neurons are located mainly in the protocerebrum of the brain. Several LK I-IR neurons were innervated only to the CC. Immunogold labeling also reveals that the CC has both LomTK I- and LK I-IR axon terminals, while the CA contains LomTK I- IR axon terminals. Especially, the LK I-IR axon terminals located in the CC are in close contact with the glandular cells, suggesting that the LK I may play an important role on releasing secretory substances in the glandular cells.