That big long-legged fly isn't a mosquito; it doesn't eat mosquitoes, and it's harmless. A bit of insect myth-busting.
Have you seen strange lumpy growths on your plants? They might be galls caused by tiny wasps or flies.
Late spring and early summer there is a short-lived but massive mayfly invasion. Millions and millions of the fluttering insects rise up from the lake and into the air in thick clouds.