The Upanishads, Part 1 (SBE01)
Chapters
Kena-Upanishad: First Adhyaya: First Khanda

^202:1 Vangah is explained by vanagata vrikshah; avagadhah is explained by vrihiyavadya oshadhayah; irapadah is explained by urahpadah sarpah. Possibly they are all old ethnic names, like Vanga, Kera, &c. In Anandatirtha's commentary vayamsi are explained by Pisaka, Vanavagadhas by Rakshasa, and Irapadas by Asuras.

^202:2 Three classes of men go to Naraka (hell); the fourth class, full of faith and desirous of reaching the highest world, worships Agni, Vayu, and other gods. Comm.