Periodically, at night, a swarm of flying insects congregates on the front porch. That’s a trick, because it is screened to prevent insects from congregating. Ergo, they are coming from inside the porch.
A little investigation proved that they are coming out of the soffit (the underside of the roof).
Today I worked on an outdoor fountain, preparing it to receive a new pump. Tomorrow I will mix a batch of poison and spray in the attic to kill the flying insects.
Onward and upward.