Abstract
The ecology and life history of Euurobracon yokahamae (Dalla Torre, 1898) are being clarified rapidly in recent years. However, its egg-laying has not been observed because the behavior is done using thin tunnels made by cerambycid larvae of Massicus raddei. For the direct observation of oviposition behavior of E. yokahamae, we tried to use an industrial endoscope. As a result, we firstly succeeded to confirm the position of the ovipositor at laying to the host, and were able to record it in the photographs. In addition, four examples of parasitized pupas (and pre-pupa) of Massicus raddei by E. yokahamae were newly confirmed in the chestnut tree. Subsequent continuous observation under the rearing conditions almost revealed the life history of E. yokahamae including larvae, pupas, and emergence.
