Mosquitoes

Shelves installed by Premier Closets, in my pending study, to make attractive bookcase out of spare closet.  Spent laborious day touching up new paint and moving books onto new shelves, vaccuuming, etc.  Tonight went up to admire work and anticipate many productive and satisfying hours. Discovered ceiling swarming with whining mosquitoes.  What the...?  Sprayed toxins, closed door, put towel against door crack.  We've rarely been bothered by mosquitoes, attributing that to neighborly dragonflies and bats. Not sure what triggered this particular infestation. Unseasonably warm weather? Discouraging moment in The Swamp.