The alternate generations of five species of gall-making cynipids on Garry oak, Quercus garryana Douglas, have been newly ascertained. Bisexual and agamic generations of each species have been reared through complete life cycles. All have been identified to species; three generations are described for the first time; two new synonyms and one new combination are given.

Morphology of the adults is relatively consistent between alternate generations, but specific characteristics, habitat, and gall-form may differ widely. Distinguishing features of the generations are presented, including life histories, descriptions and photographs of galls, and comments on associate insects. Taxonomic bibliographies are given, and references are listed.

Three species of Pycnopsyche occur in West Creek, the larvae inhabiting allochthonous organic materials. The rapid growth, and early aestivation and emergence of the rarest species, P. scabripennis (Rambur), diminishes interspecific interactions between larvae. P. gentilis (McLachlan) and P. luculenta (Betten) are contemporaneous and the larvae are similar in size but differ in case materials and habitat preferences. Adult males of each species differ in the peak time of arrival at light when active on the same night. The life history and behaviour patterns are discussed in relation to the coexistence of congeneric species.

Stemmatosteres kuchari n. sp. from Alberta, Canada, is described and illustrated.