Prior to the lunar or Demetrian cultural stage and the patriarchal, or solar, cultural stage, J J Bachofen identified, through the study of ancient myths, and even earlier stage which he called “hetaerism”. Julius Evola gives the name “Telluric Race” in the Sintesi to the guiding spirit of that age.
In such periods, marriage is unknown and women held in common. Bachofen explains:
Woman is not endowed with all her charms in order to grow old in the arms of one man: the law of matter rejects all restrictions, abhors all fetters, and regards exclusivity as an offense against its divinity.
Unlike the Demetrians, who developed agriculture, the Tellurians were associated with the natural flora and fauna of the marshy lowlands, as well as swamp cults. This life is represented by witches, who were involved with herb collecting and concoctions using lower life forms like toads and lizards. The battle between the Telluric and Solar impulses is demonstrated, for example, in the Nordic legend of the Virgin Spring, with Ingeri as the exemplar of the former and Karin of the latter.
The struggle between the Titans and the Olympic gods can also be understood in this context. The mlecchas were a degraded Telluric warrior caste, which the avatar Parashurama came to destroy.
Evola mentions that Keyserling comment in a few of his books, but I haven’t been able to locate the reference. The Italian title does not correspond to his published works in German or English.