Box elder bugs are... bugs, not beetles. Of the order Hemiptera. They do little damage, but are annoying as all getout, covering sunny walls, getting into houses when weather gets cool, and if you smush um they leave a red smear. A wall crawling with all sizes of them looks real creepy.
If you spray them with a mild soap and water solution, they keel right over. The dried soap solution kills those that come along later.
Round Up is a plant killer, it has little effect on insects. However you may have solved your problem, if you have box elder trees, you have box elder bugs. To a lesser extent they feed on ash and maples. But box elder tree= box elder bugs.
Keep an eye out,Junk, they hide in siding and work their way in, to get away from cool weather. They "hibernate" for a while, then when it gets cold enough to turn on heat, they think its spring and move towards warmth.