[1] From the scholia to Aristophanes, Acharnians 11, where he is mentioned (web address 1). See also psi 178, and generally OCD(4) Theognis(2). As the name is not uncommon, prosopographers have seen no reason to follow the scholiast and identify him with the Theognis who, twenty years later, was one of the ruling oligarchic Thirty (Xenophon, Hellenica 2.3.2, etc.). See further, next note.
[2] Abbreviated from Harpokration theta6 Keaney; also in Photius. Harpok. was commenting on the mention of Theognis the oligarch in Lysias 12.6ff., but then went on to note the allusion to a poet called Theognis [meaning Th. of Megara: theta 136] in Isocrates 2.43, and to give a quotation from him. In its abbreviated from, here, this material joins on to the first paragraph of the entry rather clumsily.