All life stages and both sexes of Bryophaenocladius faegrii sp. n. are described. The pupa especially has characters not previously found in the genus, including a thoracic horn and several pairs of setae on the cephalic sheath and on tergite IX. Also the male, female and larva exhibit characters in new combinations. Corrected and emended generic diagnoses for the different life stages are given, and aspects of the ecology of the species are discussed.