Phyllonorycter mongolicae is a moth of the family Gracillariidae. It is known from the islands of Hokkaidō, Honshū, Kyūshū and Shikoku in Japan.Global Taxonomic Database of Gracillariidae (Lepidoptera)
The wingspan is 5.5–7 mm.
The larvae feed on Quercus crispula, Quercus mongolica and Quercus serrata. They mine the leaves of their host plant.
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