What are these? We're new to MD and have never seen these burrowing bees before. I'll rather not eliminate them if they're beneficial but it's in an area where kids play. Any info is appreciated!
These are mining bees. They are non-aggressive beneficial pollinators which nest singly in the ground and do not sting. Control should be avoided if possible. The females burrow and lay an egg and provision it with an insect pest for the new hatchling to eat.
Their activity is usually brief about several weeks. They like exposed soil and good drainage. In flower beds, you may want to lay landscape fabric down and cover with several inches of mulch to discourage them. In lawn areas, seed in the fall to thicken up your stand of turf. See our website for more information http://extension.umd.edu/learn/mining-bees