We have isolated neuropeptides of the AKH/RPCH family from extracts of whole heads of four termite species (Mastotermes darwiniensis, Microhodotermes viator, Hodotermes mossambicus, and Trinervitermes trinervoides) using the effect of mobilizing lipids in Locusta migratoria for bioassay. Isolation was essentially achieved by two steps of reversed-phase chromatography (on phenyl-support followed by C-18). The peptides were identified by Edman degradation after deblocking with oxoprolyl peptidase. Each termite species contained only one AKH/RPCH family member. The primary structure in M. darwiniensis and T. trinervoides is pGlu-Val-Asn-Phe-Ser-Pro-Asn-Trp-NH2, a peptide previously found mainly in cockroaches and code named Pea-CAH-I. The peptide from M. viator has the primary sequence pGlu-Ile-Asn-Phe-Thr-Pro-Asn-Trp-NH2; it is a novel member of the family and is code-named Miv-CC (Microhodotermes viator corpus cardiacum peptide). Phylogenetic relations between the known cockroach and mantid AKH/RPCH octapeptides and the termite peptides from this study could be revealed employing the parsimony method. Based on a computer analysis, using PAUP 3.1.1., we concluded that termites are plesiomorphic with regard to cockroaches, and mantids are the sister taxon to the termite/cockroach group.