Keys, descriptions, and biological notes are given for 8 species and 2 subspecies of Pemphiginae which are known to be, or are strongly suspected of being, associated with roots of conifers in North America. The species and subspecies are divided into 3 genera: Prociphilus americanus (Walker), P. carolinsnsis, n. sp., P. piniradicivorus, n. sp., P. alnifoliae alnifoliae (Williams), P. alnifoliae arbutifoliae, n. ssp., P. alnifoliae fitchi Baker & Davidson, Rhizomaria piceae Hartig, Stagona crataegistrobi, n. sp., S. piceaerubensis, n. sp., and S. xylostei (De Geer).