Adults and subimagos of Rhithrogena species have two long tails, and readily visible hind wings. R. germanica can only be distinguished from related species such as R. semicolorata (the only other Rhithrogena species in the United Kingdom) by the presence of a dark spot on the femora of the legs.[4] A similar species, Ecdyonurus venosus (the late March brown or false March brown) is more widespread in Great Britain, but emerges later in the year than R. germanica.