The present study describes for the first time in Acerentomon sp. the distribution of glutamate decarboxylase-like immunoreactivity. The presence of this GABA-synthetizing enzyme was described in: pharynx wall, cephalic muscles, posterior part of the supraesophageal ganglion, abdominal glands, neuropil near to the posterior ganglion, cuticular muscle insertion and in sensilla. Furthermore the use of fluorochrome-conjugated lectins was tested in order to visualize taxonomic features (like pores and setae) on whole mount fixed Protura specimens. The development of a lectin-based technique could render more precise the species determination, allowing a more accurate identification.