from
The Collaborative International Dictionary of English v.0.48
cabbage worm \cab"bage worm`\, cabbageworm \cab"bage*worm`\n.
(Zool.),
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
rap[ae]}). The cabbage cutworms, which eat off the stalks of
young plants during the night, are the larv[ae] of several
species of moths, of the genus {Agrotis}. See {Cutworm}.
larva of a cabbage butterfly.
[WordNet 1.5]