Charles Ellicott Commentary Psalms 105:34

"He spake, and the locust came, And the grasshopper, and that without number," — Psalms 105:34 (ASV)

Caterpillars.—To the locust, ‘aarbeh, exclusively mentioned in Exodus, the psalmist adds, as a poetical synonym to suit his parallelism, caterpillar (yelek), a word occurring in Joel 1:4; Joel 2:25; Nahum 3:15; Jeremiah 51:14; Jeremiah 51:27. By derivation, the word means “licker” and is possibly used in a wide or general sense for insects of the locust kind. (See Bible Educator, IV. 294.)