From the scholia (F.Dubner) to Aristophanes, Wealth [Plutus] 907 and 910; see further below.
[1] Both xorhgi/a and trihrarxi/a -- technical terms in other contexts -- are frequently used together in the classical period (especially by Demosthenes) in reference to public administration.
[2] From the scholia to Plutus 907, where the sycophant says tw=n th=s po/lews ei)m’ e)pimeleth\s pragma/twn kai\ tw=n i)di/wn pa/ntwn; "I am curator of public matters and of all the private ones" (web address 1). The gloss develops the sycophant's thought; he is claiming to be a model volunteer prosecutor of public suits, protecting the public interest.
[3] A version of a scholion on Plutus 910, now explaining the common opinion in Athens about sycophancy. "Just how intrigued Athenians were by the idea of the “sycophant” can be inferred from how often the comic poet Aristophanes brought sycophants on stage as figures of ridicule and universal disdain. In his Acharnians (425 BC), for example, sycophants appear in two episodes (818-29, 908-59) in the form of marketplace informers, who threaten legal action against Dikaiopolis, the comedy’s protagonist, for violating Athens’ ban on the import of goods from hostile states. In his Birds (414 BC), Aristophanes introduces a hyperactive sycophant who makes his living by harassing members of Athens’ subject states in the Athenian courts (1410-69). In Aristophanes’ Plutus (388 BC), the intruding sycophant claims to be a model volunteer prosecutor of public suits, protecting the public interest (850-958). Each sycophant is mocked and then driven off the stage by Aristophanes’ protagonists” (Matthew R. Christ, Sycophancy and Attitudes to Litigation: web address 2).