The distribution of western corn rootworm,Diabrotica virgifera virgifera, larvae in corn roots was mapped through the larval period in three different plantings of corn in 1984 and 1985. Roots were boiled in a solution of lactophenol and acid fuchsin to fix and stain the larvae. First instars were found in the seminal roots as well as roots on the first five whorls. Significantly more first and second instars were oriented toward the root tip than the root base. Over time, larvae tended to move into the roots of the newer whorls. In separate laboratory experiments, cut and uncut corn roots were infested with first instars. Orientation of first instars in uncut roots was similar to that seen in the field. Removing the root tips 1 h before or 24 h after infestation resulted in an equal number of larvae orienting toward and away from the root terminus, whereas tip removal 24 h before infestation resulted in more first instars orienting toward the root base.