HYMENOPTERA, Cynipidae (Cynipinae) (Cynipoidea)
The Cynipinae, or gall wasps, are a large group, and many species are quite common. They are small to minute, usually black insects that are distinguished by their shape and wing venation. The abdomen is oval, compressed, and shining, and the second tergum covers about half or more of the abdomen. The Cynipinae differ from the Charipinae in that they are larger and the thorax usually has coarse sculpturing.
Each species of gall maker forms a characteristic gall in a particular part of a plant, the galls being much more often noticed than are the insects. Many of the gall wasps form galls on oak. Some galls harbor a single insect, while many insects develop in others. The inquilines among the gall wasps live in galls made by some other gall insect. Most of the gall wasps are of little economic importance, but some of their galls have been used as a source of tannic acid and others have been used as a source of certain dyes.
Many gall wasps have a complex life history with two different generations a year. The summer generation is spent in one type of gall, and the wasps, consisting entire of females emerge in autumn. They reproduce parthenogenetically. The eggs of this generation hatch and develop in a different type of gall, and the adults that emerge in the early part of the following summer contain both males and females. Both the adult insects and the galls of these two generations may be quite different in appearance (Borror et al., 1989).
Nieves-Aldrey, J.L.; Liljeblad, J.; Nieves, M.H.; Grez, A.; Nylander, J.A.A. 2009: Revision and phylogenetics of the genus Paraulax Kieffer (Hymenoptera, Cynipidae) with biological notes and description of a new tribe, a new genus, and five new species. Zootaxa, 2200: 1-40.
Ronquist, F. 1999: Phylogeny, classification and evolution of the Cynipoidea. Zoologica scripta, 28: 139-164.