The headword, in the dative plural, is evidently quoted from somewhere. Adler took the source to be Homer, Odyssey 5.471, where θάμνοισ' occurs, and she compared also Hesychius and a scholion on Homer, Iliad 11.156. However, C. Theodoridis in his Photius edition (vol.II p.C) shows that the true source is Aristophanes, Birds 615; see the scholia there.
See also theta 39, and under epsilon 1440 and omicron 477.