Life cycle closure of Cerroneuroterus minutulus (Giraud, 1859) with C. aggregatus (Wachtl, 1880) (Hymenoptera: Cynipidae: Cynipini): experimental, taxonomic and molecular approaches.

The life cycle of Cerroneuroterus minutulus (Giraud, 1859), a species previously known only from its asexual generation, is closed. Our study demonstrates that C. minutulus exhibits the heterogony typical of Cynipini species, with alternating sexual and asexual generations. The identity of the sexual generation is demonstrated by laboratory experiments and confirmed by molecular data, with Cerroneuroterus aggregatus (Wachtl, 1880) determined to be the sexual generation, and junior synonym, of Cerroneuroterus minutulus (Giraud, 1859). Illustrations and diagnoses for adults and galls, observations on biology and distribution information are provided as is a detailed redescription of the sexual generation of C. minutulus.

The experimental life cycle closure of Andricus truncicolus (Giraud, 1859) (Hymenoptera: Cynipidae: Cynipini) and taxonomic description of its sexual generation.

The life cycle of Andricus truncicolus (Giraud, 1869), a species previously known only from its asexual generation, is closed. Laboratory rearing and field sampling have revealed the sexual generation of this species, which develops in a hypertrophic degeneration of the terminal or lateral shoot buds appearing as a muddled agglomerate of leaves on Quercus, section Cerris oaks. We describe for the first time the newly discovered sexual generation of A. truncicolus and provide illustrations and diagnosis for adults and galls of both generations, further observations on biology and information on the species distribution.

Andricus cydoniae Giraud, 1859 Junior Synonym of Cynips conifica Hartig, 1843, as Experimentally Demonstrated (Hymenoptera: Cynipidae: Cynipini).

We demonstrated the life cycle closure of Cynips conifica Hartig, 1843 (presently Andricus conificus), previously supposed on the basis of molecular data, and the identity of the sexual generation, through laboratory experiments. As a consequence, Andricus cydoniae Giraud, 1859 became a junior synonym of A. conificus (Hartig, 1843). We provide illustrations and a diagnosis for adults and galls, observations on biology, and information on distribution. Moreover, as sexual galls of A. conificus cannot be distinguished from those of Andricus multiplicatus, a detailed comparison between sexual galls and adults of these two species is reported.

Rediscovery of Cerroneuroterus apenninus (Trotter, 1923) (Hymenoptera: Cynipidae: Cynipini) a valid species from Italy with description and neotype designation.

Neuroterus apenninus Trotter, 1923 associated with a Cerris section oak, Quercus cerris L., was rediscovered in Italy in 2017. Alessandro Trotter (1903) described a leaf gall collected on Q. cerris from the Italian Apennines; he did not obtain the gall inductor and ascribed the galls to the genus Neuroterus, based on morphological similarity with other Neuroterus galls. We have found the same gall and obtained the gall inducer. Detailed study of morphological characters of adults revealed that the species belongs to the genus Cerroneuroterus Melika Pujade-Villar, 2010. The asexual generation of Cerroneuroterus apenninus comb. n. is described for the first time, a neotype is designated, and a diagnosis, host associations and biological notes are given; an identification key to the Western Palaearctic Cerroneuroterus species is provided.