The district board shall be called "The board of trustees of . . . . . . mosquito control district."
Each member of the board appointed by the governing body of a city shall be an elector of the city from which he or she is appointed and a resident of that portion of the city which is in the district.
Each member appointed from a county or portion of a county shall be an elector of the county and a resident of that portion of the county which is in the district.
Each member appointed at large shall be an elector of the district.