Jamieson, Fausset and Brown on Nahum 3:17

17. Thy crowned--Thy princes (Re 9:7). The king's nobles and officers wore the tiara, as well as the king; hence they are called here "thy crowned ones."

as the locusts--as many as the swarming locusts.

thy captains--Tiphsar, an Assyrian word; found also in Jr 51:27, meaning satraps [Michaelis]; or rather, "military leaders" [Maurer]. The last syllable, sar means a "prince," and is found in Belshaz-zar, Nabopolas-sar, Nebuchadnez-zar.

as the great grasshoppers--literally, "as the locust of locusts," that is, the largest locust. Maurer translates, "as many as locusts upon locusts," that is, swarms of locusts. Hebrew idiom favors English Version.

in the hedges in the cold--Cold deprives the locust of the power of flight; so they alight in cold weather and at night, but when warmed by the sun soon "flee away." So shall the Assyrian multitudes suddenly disappear, not leaving a trace behind (compare Pliny, Natural History, 11.29).