National Geographic Kids (K-5)

Nemours KidsHealth: Hey! A Mosquito Bit Me! (K-5)  

Britannica Kids (K-5)

Britannica Kids (Grades 6-8)

Britannica Kids | Encyclopedia (Grades 9 & up)

Why do mosquitoes suck your blood?  (all ages)

Science Alert (all things mosquitoes) (all ages) 

FDACS (Florida Department of Agriculture and Consumer Services) (mosquito prevention & more) (all ages)