Neelus murinus is a moderately common species that is found almost exclusively in caves, though Peter Shaw has found it reaching in high numbers in dense moss in a quarry on Box Hill.. It is blind and is slightly larger than the other Neelidae, occasionally reaching 1.0 mm in length. The empodium of the foot is about half as long as the claw (Fig. 1) and the edges of the mucro are serrated (Fig. 2). The third (ant3) and fourth (ant4) antennal segments are clearly separate with ant 3 being of similar width to ant 4 (Fig. 3). The sensory setae on ant4 are long(Fig. 3). The ventral tube bears a small posterior projection (a character shared with Neelides minutus, but not with Megalothorax minimus).