Diagnostic character traits used in the identification key. A Areolet (Megarhyssa babaulti holotype) B open areolet (http://mus.utu.fi/ZMUT.5788) C subalar prominence flange (http://mus.utu.fi/ZMUT.2520) D subalar prominence without flange and dorsal margin of mesopleuron with flange (http://mus.utu.fi/ZMUT.5853) E dorsal margin of mesopleuron without flange (SAMC SAM–HYM–P048018) F elliptical apical horn of metasoma (http://mus.utu.fi/ZMUT.5766) G half-elliptical apical horn of metasoma (http://mus.utu.fi/ZMUT.5853) H frons without carinae (http://mus.utu.fi/ZMUT.4920) I frons without lateral carinae (http://mus.utu.fi/ZMUT.3234) J striate tergite 3 (http://mus.utu.fi/ZMUT.5788) K punctate tergite 3 (http://mus.utu.fi/ZMUT.5663) L hypostomal carina raised into elevated flange (SAMC SAM–HYM–P048018) M hypostomal carina raised into low flange (E. shaka holotype) N half-elliptical apical horn of metasoma (http://mus.utu.fi/ZMUT.5663) O elliptical apical horn of metasoma (E. shaka holotype). Image A is from van Noort (2019). Image D has been flipped horizontally.