I have found a product called "Buhach" to be a very good deterrent for most any type of insect, flying or otherwise. You can usually find it at a good garden or feed store. Call first, because they don't all carry it. It is organic, being made up of powdered Pyrethrum flowers.
To fumigate your house, pour some of the powder into a metal lid off of a jar, or into a tuna can, or aluminum pan/pie tin. Light it with a match, it burns very slowly - like a smudge pot. Remember to close all the doors and windows and leave the house for a couple of hours. Have the smudge set up on a trivet or another fire proof thing like a stove top, etc., so that as Buhach heats up, it will not cause a bigger problem - like a house fire - while you are gone.
Another use for this product is for the faces of animals that are getting bit up by gnats, etc. (I use it on my dogs). Mix a little bit of the powder with some cooking oil and spread it around their snouts, eyes, etc. Be careful not to get it into their eyes though. This does provide them with some relief, if the biting insects are bad in your part of the world.
http://www.plantitearth.com/pestcontrol2.html
Buhach Company (800)284-2241.
http://www.the-scientist.com/yr1991/june/research_910610.html