Lewis & Short

Thespĭae, ārum, f., = Θεσπιαί, a town in Bœotia, at the south-eastern foot of Helicon, now the village of Lefka, near Rimokastro, Plin. 4, 7, 12, § 25; 36, 5, 4, § 22; Cic. Verr. 2, 4, 2, § 4; 2, 4, 60, § 135; id. Fam. 13, 22, 1; Liv. 42, 43 al.
Hence,

  1. A. The-spĭus, a, um, adj., of or belonging to Thespiæ, Thespian; moenia, Val. Fl. 1, 478.
    Plur.: Thespĭi, ōrum, m., the inhabitants of Thespiæ, Arn. 6, p. 196.
  2. B. The-spienses, ĭum, m., the inhabitants of Thespiæ, Cic. Verr. 2,4,60, § 135.
  3. C. Thespĭă-cus, a, um, adj., of or belonging to Thespiæ, Thespian: moenia, Val. Fl. 1, 93: luci, on Mount Helicon, Stat. S. 2, 7, 16.
  4. D. The-spĭădes, ae, m., the Thespian, of Argus, the builder of the ship Argo, Val. Fl. 2, 367; 1, 124.
  5. E. Thespĭăs, ădis, adj. f., Thespian: Musae (as dwelling on Mount Helicon), Ov. M. 5, 310; also called, absol., Thespiades, Varr. L. L. 7, § 20 Müll.; Cic. Verr. 2, 4, 2, § 4; Plin. 36, 5, 4, § 39.