We describe the larva of Matronoides cyaneipennis Förster, 1897, based on an incomplete, dried F0 specimen collected at Mt Kinabalu, Sabah, in 1964, and held at the Natural History Museum, London. Since its collection nearly 60 years ago no other specimen has come to light despite considerable searching of its habitat. Identification is by supposition, but given its provenance the identity of the specimen is not in doubt. All diagnostic features remain intact. The larva is compared with those of the related genus Neurobasis, especially the potentially syntopic N. longipes from which it differs markedly.