Pireninae (Hymenoptera: Pteromalidae) of Papua New Guinea: key to genera and description of new taxa Author Mitroiu, Mircea-Dan John T. Huber text Mémoires du Muséum national d'Histoire naturelle 2016 209 307 320 journal article 1243-4442 Genus GASTRANCISTRUS Westwood, 1833 Figure 1 Gastrancistrus Westwood, 1833: 444 . Type species. Gastrancistrus vagans Westwood, 1833 ; by monotypy. REMARK – According to Bouček (1988) the genus Gastrancistrus can be separated from Premiscogaster Girault, 1933 by the shape of the antenna: Premiscogaster has a conspicuously asymmetric clava and pedunculate flagellomeres, whereas Gastrancistrus has a symmetric clava and not or hardly pedunculate flagellomeres. However, according to Bouček (1988) and my personal observations, Premiscogaster is very close to Gastrancistrus , some diagnostic characters overlapping in the two genera. For example, Bouček (1988: 475) wrote that “all [ Premiscogaster ] species examined have […] a deep round or oval fovea on the upper part of the scrobes (at least in the females) and at least some coarse punctures on the sides of the frons. […] The deep fovea on the scrobes is present also in Gastrancistrus punctatiscutum , which also has coarse punctures on the head and is similar in colour to the typical Premiscogaster . However, the antennal flagellum in that species is simple and compact, with a normal, symmetric, 3-segmented clava”. Moreover, in many species from the PNG material examined, the flagellomeres before the clava are distinctly pedunculate, a deep scrobal fovea is present, but the clava is virtually symmetric (Figure 1). According to Noyes (2015) , there are 18 species of Gastrancistrus and two species of Premiscogaster described from the Australasian region, mostly by Girault. Without a revision of both genera, I therefore hesitate to describe any new species.