( ( ( ( ( ( ( The majority ) ( of katydids ) ) ( are herbivores ) ) , ) but ) ( ( a few ) ( are omnivores ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN majority)) (PP (IN of) (NP (NNS katydids)))) (VP (VBP are) (ADJP (JJ herbivores)))) (, ,) (CC but) (S (NP (DT a) (JJ few)) (VP (VBP are) (ADJP (JJ omnivores)))) (. .)))
The majority of katydids are herbivores, but a few are omnivores.
(ROOT (S (NP (NNS Mammals)) (VP (MD may) (RB either) (VP (VB be) (NP (NNS herbivores) (, ,) (NNS omnivores) (CC or) (NNS herbivores)))) (. .)))