A noun for a “small insect, fly” appearing in notes from 1968 as an example of a primitive monosyllabic noun that survived in modern Quenya (VT47/35). Its primitive form was originally glossed “small bird”. I think it might apply to other tiny insects like mites or gnats, based on its conceptual precursors. Likely it is related to the root √PI(N) for tiny things.
Conceptual Development: In the Qenya Lexicon of the 1910s Tolkien had ᴱQ. pī “speck, spot, dot, mote” and ᴱQ. pin or pink “a little thing, mite”, the latter also serving as a diminutive ending, all under the early roots ᴱ√PINI, ᴱ√PIKI, or ᴱ√PĪ (QL/73). It is unclear whether or not ᴱQ. pin(k) “mite” could refer to an insect or only a tiny thing. In the Declension of Nouns of the early 1930s, Tolkien had ᴹQ. mí “fly” (PE21/40).
pí noun "small insect, fly" (VT47:35)