The karyotype, morphology of adult, pupae and larvae, and the ecology of Glyptotendipes aequalis Kieffer (1922) are described from material from Finland, and a neotype from the (probably) original German material is designated. 2n = 8. Ist, IInd and IIIrd chromosomes are metacentric, IVth acrocentric. The IVth chromosome has a nucleolus and a Balbiani ring. G. aequalis is karyologically closely related to G. caulicola, differing by a simple inversion step.