Over 11,000 microlepidoptera pupae were randomly collected over a one week period in June 1972 from a mixed oak forest in central Pennsylvania. Of the adults emerging (58.87%), 98.67% wereArchips semiferanus(Walker). Males emerged earlier than females; a sex ratio of 1.22 ♂:1 ♀ was found.Six Hymenoptera pupal parasites were observed, withItoplectis conquisitor(Say) (3.52%) andPhaeogenes gilvilabrisAllen (2.62%) the most common.A. semiferanusis the 1st reported host forP. gilvilabris. The male parasites emerged earlier than the females with the following sex ratio:I. conquisitor, 2.10 ♂:1 ♀;P. gilvilabris, 3.70 ♂: 1 ♀. In general male Hymenoptera parasites emerged from maleA. semiferanuspupae, and female parasites from female hosts.