(Something adorable for a little girl! Notice the elongated bodice meant to represent the insect body; this is found on women's insect costumes as well. I don't know enough about butterflies to have any idea what makes this particularly Canadian, but there are non-Canadian butterfly costumes as well for both women and girls and the general style could be adapted to any species of butterfly.)
Bodice of green plush elongated into a point which falls on to the short yellow tulle skirt; short, puffed sleeves; gauze wings at back forming tunic; butterfly on head; green gloves and shoes with butterflies; butterfly fan.
Sources:
Holt, Ardern. Fancy Dresses Described, 5th Edition. London: Debenham & Freebody, 1887.
Holt, Ardern. Fancy Dresses Described, Sixth Edition. London: Debenham & Freebody, 1896.
The 1896 edition of Holt may be found online at the University of Wisconsin Digital Collections.