From 深 (mi, "deep") + 山川 (sansen, "mountains and rivers") + 蜻蛉 (tonbo, "dragonfly," "damselfly").
深山川蜻蛉(みやまがわとんぼ) or 深山川蜻蛉(ミヤマガワトンボ) • (miyamagawatonbo)