Government agencies in Idaho and Utah suggest vacuuming (using a Shop-vac or other brand of workshop vacuum) any swarms that get inside, and establishing routine insecticide treatments around the perimeter of the house or building as well as window wells, and door frames. Prevention of invasion is easier than removal, so raking up and destroying fallen elm seeds, and inspecting firewood before bringing it indoors are recommended.
Larval Elm Seed Bugs feed on the seeds of elm trees during the spring and early summer. They are therefore likely to be found in neighborhoods or regions where elms are present.
Our thanks to Fred and Jan T. in Idaho for their assistance in identifying this insect.