Acamptocladius Brundin, 1956 is shown to be a senior synonym of Phycoidella Saether, 1971, and the generic diagnosis emended. A new combination, Acamptocladius dentolatens (Saether, 1971), is established. The male and female imagines of A. submontanus are redescribed and the possible larva described. A new species, A. reissi, is described in all stages and both sexes. A key to the three species is given for all stages and both sexes. All larvae have been found in acid and humic pools and lakes. Some presumed first instar larvae found in unionid mussels may belong to Acamptocladius.