HETEROCHTHONIIDAE Grandjean, 1954

In his first notes on the Enarthronota, Grandjean (1947) classified Heterochthonius among the Cosmochthoniidae; he pointed out that the genera Cosmochthonius and Heterochthonius show some analogy in habitus, but are thoroughly different in many important characters. In 1954 he created a separate family Heterochthoniidae, characterized among others by the possession of eyes (which is a unique character) and by the lack of genital tracheae (the presence of which is a special character of the Cosmochthoniidae).