Phyllonorycter obscuricostella is a moth of the family Gracillariidae. It is known from Connecticut, Illinois, Kentucky, Pennsylvania, Maine and New York in the United States. The wingspan is 6-6.5 mm. The larvae feed on Ostrya species, including Ostrya virginiana and Ostrya virginica. They mine the leaves of their host plant. The mine has the form of a small tentiform mine on the underside of the leaf. They are usually located between two veins. The pupa is formed inside of a thin silken web which occupies an entire half of the mine. References External links mothphotographersgroup Phyllonorycter at microleps.org obscuricostella Moths of North America Moths described in 1859