In nutritional studies with insects such as the pale western cutworm, Agrotis orthogonia Morr., large numbers of larvae must be fed and observed regularly in the laboratory. Moreover, because these insects are cannibalistic they must be reared in isolation. In our laboratory 60- by 15-mm petri dishes (Jacobson and Blakeley 1957) are used as rearing containers for this insect (Kasting and McGinnis 1967). Originally, petri dishes, containing a single insect, were stacked three deep in wooden trays. The trays, each holding 60 dishes, were then stacked to conserve space. Feeding and observation of the larvae, usually done at regular intervals, often daily, necessitated removing the dishes from the trays and spreading them on a bench.