The evolution, development and function of the embryonic and larval peripheral nervous system (PNS) were investigated in a number of dipteran species, including Aedes aegypti, Hermetia pallescens, Lucilia cuprina, Bactrocera tryoni and Drosophila melanogaster. Comparative immuno-cytochemical data was generated for developmental proteins in the embryonic PNS and degenerative PCR was employed to identify homologous proneural genes amongst the species. Immunocytochemistry revealed aspects of sense-organ evolution amongst the Diptera, particularly an increase in sense-cell number and number of sensilla comprising proprioceptive organs in the crawling versus swimming larvae. The function of putative proprioceptive cells was investigated via mutant analysis and laser ablation. Results indicate that the multiple-dendrite (md) and bipolar-dendrite (bd) neurons contribute in a cumulative and roughly equal fashion to maintain peristaltic waves in crawling larvae. This work highlights the usefulness of the dipteran PNS as a model of adaptive evolution that can be investigated via developmental mechanisms.