BERNIE MAGRUDER AND THE BATS IN THE BELFRY There are strange goings-on once again in Middleburg, and Bernie Magruder is determined to get to the bottom of things, and maybe get his picture in the paper in the process. Someone has put up posters all over town warning townspeople that the dreaded Indiana Aztec bat, whose bite is often fatal, has been sighted in the area.   What's more, the town is in a political uproar over the bells recently placed in the church belfry that every hour -- twenty-four hours a day -- chime out the hymn "Abide with me." Placed there in accordance with the will of town benefactor Eleanor Scuttlefoot so that her surviving husband will always be reminded of her, the incessant pealing of the bells is driving the town mad.   Who put up all those posters about a species of bat no one has ever heard of? What can the townspeople do to return some peace to their lives? And are the bats that Bernie and his family see swooping about the belfry the dreaded Indiana Aztecs? Bernie Magruder and his friends Georgene and Weasel set out to answer these questions in this new volume in Phyllis Reynolds Naylor's hilarious series about the Magruder family who live in and operate Middleburg's famous Bessledorf Hotel.