Etainiathoraceleuca van Nieukerken, Epstein & Davis, sp. nov. is the second native American species of Etainia Beirne, 1945, and the second known Etainia species feeding on Ericaceae. The species is known from light-collected adults in the USA (California, Arizona) and Canada (Ontario). These were linked via DNA barcodes to larvae that make short leafmines on Arbutus and Arctostaphylos species, then continue feeding in stems and branches, causing damage in nurseries and planted trees in Sonoma and Marin Counties, California. The holotype was accidentally reared from Arbutusarizonica, without observing the damage. Life history and damage are described in detail. Damage in Arctostaphylosuva-ursi found in Washington State probably belongs to E.thoraceleuca, which is a sister species to the European E.albibimaculella (Larsen, 1927).
Keywords: Arizona; California; Canada; United States; insect damage; leafmines; stem mines; taxonomy.