The purpose of this application, under Article 23.9.5 of the Code, is to conserve the specific name Coluber irregularis Leach in Bowdich, 1819 (currently Philothamnus irregularis) for the African northern green bush snake. The name was placed on the Official List by a ruling in Opinion 328. This name is a junior primary homonym of Coluber irregularis Bechstein, 1802 (currently Boiga irregularis), used for the brown tree snake, known from Indonesia, Australia, Papua New Guinea and Melanesia, and infamous for its invasive colonization of Guam. Both names are in use and are not considered congeneric. It is proposed that the name Coluber irregularis Leach in Bowdich, 1819 be conserved by ruling that it is not invalid by reason of being a junior primary homonym. In order to conserve the name Coluber irregularis Leach in Bowdich, 1819, Opinion 328 suppressed the senior synonym Coluber caesius Cloquet, 1818. In that action, the name Coluber azureus Bonnaterre, 1790 (a senior objective synonym of Coluber caesius Cloquet, 1818) was overlooked. In this paper, Coluber azureus Bonnaterre, 1790 is declared a nomen oblitum under Article 23.9.2 of the Code.