Preaestival cereal leaf beetles,Oulema melanopus(L.), that fed on the 1st blade of corn died significantly sooner than starved beetles. Approximately ⅔ of the preaestival beetles that fed on the 3rd blade of corn died with the remaining beetles aestivating. Postaestival beetles that fed on the 1st blade of corn died at the same rate as postaestival starved beetles, although they ate significantly more and lived longer than preaestival beetles. An anomaly exists between the feeding and survival of pre- and postaestival beetles in that preaestival beetles, although they ate less of the 1st blade of corn, died sooner than postaestival beetles that had eaten more. Although the 1st blade was apparently less toxic to postaestival beetles, postaestival survival on 1st-blade corn was very similar to the survival of starved beetles. Corn appears to be nutritionally unusable by postaestival beetles which may be the reason beetles avoid seedling corn in the spring. Newly emerged preaestival beetles can be distinguished from postaestival beetles because the tergites under the elytra of preaestival beetles are light yellow and remain so until several days after feeding is initiated; the tergites of postaestival beetles are dark.