Canopy properly means a gnat curtain. Herodotus tells us (ii. 95) that the fishermen of the Nile used to
lift their nets on a pole, and form thereby a rude sort of tent under which they slept securely, as gnats will
not pass through the meshes of a net. Subsequently the tester of a bed was so called, and lastly the
canopy borne over kings. (Greek, kwuwy, a gnat; kwiwpeiou, a gnat-curtain; Latin, conopeum, a
gnatcurtain.)

The gnats and midges in New England can fly through quite fine mesh screening. In formation!
I hated the ones called "no-see-ums" that attacked me when I had my outboard motor in one
hand and my fishing gear in the other.