army worm

noun

• any of a number of insect larvae which occur in destructive swarms, in particular:

  • the caterpillars of some moths, which feed on cereals and other crops and move en masse when the food is exhausted (Spodoptera and other genera, family Noctuidae). the small maggots of certain fungus gnats, which move in large numbers within secreted slime (genus Sciara, family Mycetophilidae).