The Green Mountain Opera Festival is looking for a child to play the role of Sorrow in its production of "Madama Butterfly" at the Barre Opera House on June 22 and 24. Sorrow is the son of Madama Butterfly, or Cio-Cio-San, and the American Lieutenant Pinkerton. He appears on stage for five minutes in the second act in a non-speaking, non-singing role. [...] The child could be either a girl or boy, from 4 to 6 years of age, relatively fair-skinned and under three feet tall.