Horelophus walkeri Orchymont, 1913, the single representative of the enigmatic hydrophilid subfamily Horelophinae, is redescribed and illustrated based on recently collected specimens and its external morphology is briefly compared with other groups of Hydrophilidae. The species is hygropetric, inhabiting the spray zone and still waters along streams and waterfalls; its habitat preferences are discussed based on direct observation.
A list of known specimens of H. walkeri is presented and its distribution is summarized.