(B) A pair of egg sacs of H. hidamontanus, deposited in a shallow site (water depth <10 cm) within the fountain, each sac including around 30 eggs. The egg sacs of this species are usually deposited at the base of aquatic plants (mainly Lysichiton camtschatcense), under decaying logs, among decaying leaves accumulated, and so on within the water for breeding.

At this time, overwintering larvae are found frequently in the fountain.

Accompanied Collaborators: Masaichi Kakegawa and Fujio Kishi.