Looking for a children’s picture book that I read sometime between 1969-1973. The story of a young girl and her brother, or sister, catching fireflies in a jar, on a summer night.

The children’s mother (or grandmother) finds an empty glass jar in the pantry and explains how to catch the magical fireflies (she may have caught fireflies herself, as a child).

I recall the beautiful illustrations for this story, which perfectly portrayed the inky, soft atmosphere of a summer evening, filled with hundreds of glowing fireflies. The night sky was created with dark blues and purples, perhaps in pastel chalk or watercolors.

The children’s hair may have looked silvery in the starlight.

I think the fireflies were only kept in the jar for a short time and then were released into the night air.