Emerald ash borer (Agrilus planipennis)
https://www.dnr.state.mn.us/invasives/terrestrialanimals/eab/index.html
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Emerald ash borer adults are 1/2-inch long and 1/8-inch wide with flattened backs. Photo: David Cappaert, Bugwood.org
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Emerald ash borer size comparison and tree hole. Photo: Minnesota Department of Agriculture