. . if they don’t tunnel in like the subterraneans did.
There are two ways that drywood termites can begin infesting a house. By far the most common is by when they fly in and find a good place to live (in an exposed piece of timber) and start a new colony. The second way is for a colony to hitch a ride. Often this happens when they come in with furniture, even in new furniture, but just about any lump of wood can do it- such as a bread board, ornament or violin. I’ve had reports of new hollow-core internal doors being installed with drywood termites already in them.
Inspection is the only way to know that you have them.