Anotogaster sieboldii or oniyanma (オニヤンマ、鬼蜻蜓、馬大頭) in Japanese is the largest species of dragonfly native to Japan. It can grow between 95 and 100 mm in length. It is also found in other parts of Asia.
Life cycle 
Eggs hatch within a month of being laid. The larvae live for three to five years, moulting as many as ten times and growing as large as five centimeters in length. Once this size, the larvae will feed on tadpoles and small fish. The adult dragonfly can mate and lay eggs within one to two months of metamorphosis. After mating, females head toward small creeks or ponds, not fast-moving rivers or lakes, to lay eggs. They will sometimes fly perpendicularly to the water, laying their eggs in mud or sand under the surface.
- ふしぎがわかる しぜん図鑑 こんちゅう, page 35. Froebel-Kan CO., LTD., 1999
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