Lewis & Short

1. harpax, ăgis, adj., = ἅρπαξ, drawing to itself, rapacious.
Lit., of amber and brimstone: in Syria feminas verticillos inde (i. e. ex electro) facere et vocari harpaga, quia folia paleasque et vestium fimbrias rapiat, Plin. 37, 2, 11, § 37; so of sulphur, id. 35, 15, 50, § 176 (the correct reading, see Sillig ad h. l.).