Usage patterns
〈人〉が蚊に刺されるto get bitten by a mosquito
My arm itches because a mosquito bit me.
蚊を叩くto swat a mosquito
I heard a mosquito buzzing near my ear, so I swatted it.
蚊が飛んでいるmosquitoes are flying around
On summer nights, lots of mosquitoes are flying around.
Expressions
蚊の涙pittance; a very small amount