Cabbage worm

 the larva of several species of moths and butterflies, which attacks cabbages. The most common is the toxic green larva of a white butterfly, the cabbage butterfly, (Pieris rapæ). The cabbage cutworms, which eat off the stalks of young plants during the night, are the larvæ of several species of moths, of the genus Agrotis. See Cutworm. larva of a cabbage butterfly.  [WordNet 1.5]