The classification and phylogeny of the basal Vespina （= Orussoidea ＋ Apocrita） are reconsidered based primarily on rich and well preserved material from the Middle Jurassic of Daohugou in Inner Mongolia, China. Comparatively smooth morphological transitions are traced from a Xiphydriidae-like ancestor toward Orussoidea via the Jurassic family Karatavitidae, and through Karatavitidae and the Jurassic and Early Cretaceous family Ephialtitidae independently to Stephanidae, to Evanioidea, and, via the extinct Jurassic Kuafuidae fam. nov. to the remaining Apocrita. New hypothesis is proposed concerning development of the characteristic wasp-waist of Apocrita, which is supposed to appear independently and in different ways in Evanioidea and in the rest of Apocrita. As a result, six infraorders are proposed for the suborder Vespina with the following taxonomic structure： infraorder Orussomorpha including the only superfamily Orussoidea （Karatavitidae ＋ Paroryssidae ＋ Orussidae）, infraorder Stephanomorpha with the only superfamily Stephanoidea （Ephialtitidae ＋ Stephanidae）, infraorder Evaniomorpha with the only superfamily Evanioidea of traditional composition, infraorder Ceraphronomorpha with the superfamih＇es Ceraphronoidea s. str. and monotypical Megalyroidea and Trigonaloidea, and the infraorders Proctotrupomorpha, Ichneumonomorpha, and Vespomorpha of traditional composition. The family Kuafuidae is unplaced to infraorder because it is putatively paraphyletic with respect to Ceraphronomorpha, Proctotrupomorpha, Ichneumonomorpha and Vespomorpha. Described as new are Karatavites junfengi sp. nov, Praeratavites wuhuaensis sp. nov., P. perspicuus sp. nov, Postxiphydria daohugouensis gen. et sp. nov., P. ningchengensis gen. et sp. nov., Postxiphydroides strenuus gen. et sp. nov., Praeratavitoides amabilis gen. et sp. nov., Proapocritus densipediculus sp. nov., P. sculptus sp. nov., P. longantennatus sp. nov., P. formosus sp. nov., P. atropus sp. nov., P. elegans sp. nov., Stephanogaster pristinus
Insects of the Jehol Biota,also known as the Jehol Entomofauna,can be divided into three phases,approximately corresponding to the early,middle,and late Jehol Biota.The early phase of the entomofauna is found in the Dabeigou Formation and its coeval horizons(ca.135-130 Ma).The middle phase is recorded from the lower-middle Yixian Formation(underlying the Jingangshan Bed) and its coeval strata(ca.130-122.5 Ma).The late phase is found in the lower Jiufotang Formation,the upper Yixian Formation(the Jingangshan and Huanghuashan beds) and their coeval horizons(ca.122.5-120 Ma).In major distribution areas of the Jehol Biota,the entomofauna changed greatly in species diversity with about 150 species in about 40 families and 11 orders in the early phase,a great increase up to about 500 species in about 100 families and 16 orders in the middle phase,and a decline to about 300 species in about 80 families and 14 orders in the late phase.The entomofauna can also be divided into four insect communities based on habitats or five insect groups based on feeding habits.Each community or group varied in species diversity in a similar trend to the whole entomofauna.However,it kept a comparatively stable position in the ecosystem.Of the four communities,the highest species diversity occurred in the forest community,followed by the aquatic,the soil,and the alpine communities.Of the five groups,the highest species diversity appeared in the phytophagous group,followed by the carnivorous,the parasitic,the saprophagous,and the heterophagous groups.
