The distribution of Coleophora laricella (Hbn.) and its parasites Dicladocerus spp. (D nearcticus Yosh. and D. pacificus Yosh. (Yoshimoto 1976)) and Spilochalcis albifrons (Walsh) in the crowns of western larch were determined for five classes of trees. In open-grown trees more than 7.6 m high, C. laricella densities were greater at 1.5-3.1 m than at 6.1-7.6 m above the ground, on the sunny side of a tree than on the shaded side, and on the outer half than on the inner half of a branch. In open-grown trees 3.0-4.6 m high and in trees forming a closed canopy, only the outer branch halves had significantly greater densities. The only significant variation in parasitism by Dicladocerus spp. occurred between branch halves in open-grown, non- roadside trees more than 7.6 m high, with more parasitism on the inner halves than the outer. Parasitism by S. albifrons was significantly greater at the lower crown level than at the higher in open-grown, closed-canopy, non-roadside trees that were more than 7.6 m high, and on the outer branch half than on the inner half in the same category of tree
