Ян Ларрі "Незвичайні пригоди Картка та Валі" (Казки)

The protagonists, brother and sister Karik and Valya, find a powder in Professor Ivan Hermogenovich's laboratory, eat it, and become tiny people for whom insects are extremely large creatures. The three of them and the professor spend some time in the field, in the forest, and on the river among dragonflies, butterflies, beetles, spiders, and other insects. Their extraordinary journey and amazing adventures are described in this story.