Katydids are large, usually green insects with long antennae and large wings, emminently capable of flight. Most katydids are well-camouflaged in foliage and become virtually invisible amidst greenery the identical color. Family Tettigoniidae contains about 6000 species in 1070 genera.

Katydids are largely phytophageous (plant-eating), but Wikipedia reports some species are predatory on -get this- snakes and lizards.
I'd like to see some citations for that bon mot, but they be lacking.

However, this from From Tree of Life: "Katydids are found on all continents except Antarctica and in an assortment of habitats from tropical forests (Heller 1995) and peat bogs (Vickery and Kevan 1985) to montane alpine zones 'far above the last outposts of trees'. Within these habitats, virtually all tettigoniids are associated with vegetation, particularly during inactive periods when the insects retreat into (or onto) leaves.

Most katydids are omnivorous, feeding on vegetation, seeds, carrion and occasional prey." [3] (emphasis mine)