What is a querulous kid? (From Wharton's Ethan Frome)

To be querulous means to be habitually complaining, whining.

I went after him into a low unlit passage, at the back of which a ladder-like staircase rose into obscurity. On our right a line of light marked the door of the room which had sent its ray across the night; and behind the door I heard a woman's voice droning querulously.

From Wharton's Ethan Frome.