Synergus nigrus (Hymenoptera, Cynipidae, Synergini), a new inquiline species reared from galls of Philonix nigra Gillette, 1889 (Cynipidae, Cynipini)

Quercus). Such structures are often inhabited by other cynipids, who apparently cannot induce their own galls on these plants.

These inquilinous species are primarily classified in the tribes Synergini (Synergus spp.) and Ceroptresini (Ceroptres spp.) Extensive rearing pf P. nigra galls has yielded numerous associates, including a new species of Synergus.We describe Synergus nigrus Montelongo & Nastasi sp. nov., a new species of inquilinous cynipid discovered from the eastern USA in Philonix nigra galls. This species is morphologically diagnosable, being the first Synergus with a partially smooth mesopleuron and 15 antennomeres in females.