This beautiful insect is a type of antlion (Glenurus gratus). They are beneficial predators. The adults feed on caterpillars and aphids. The larvae feed mainly on ants and other insect larvae.

If you have an interest, you might wish to submit your photo to the Maryland Biodiversity Project. This insect has been recorded in several counties of Maryland, but not yet in Frederick County.
https://www.marylandbiodiversity.com/viewSpecies.php?species=14647

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