Zootaxa 1851: 1–28 (2008) www.mapress.com / zootaxa/ ISSN 1175-5326 (print edition) Copyright © 2008 · Magnolia Press ISSN 1175-5334 (online edition) ZOOTAXA A new species-group of Dissomphalus (Hymenoptera: Bethylidae), with description of thirteen new species I. D. C. C. ALENCAR & C. O. AZEVEDO Universidade Federal do Espírito Santo, Departamento de Biologia, Av. Marechal Campos 1468, Maruípe, 29040–090 Vitória ES, Brazil. E–mail: idccalencar@gmail.com; bethylidae@gmail.com Abstract The microstictus species-group is defined by having a latero-apical filament at the ventral ramus of the aedeagus. Thirteen new species are described and illustrated: Dissomphalus balteus, D. divaricatus, D. forceps, D. incurvatus, D. osseus, D. paululus, D. perparvus, D. perturbatus, D. perventriosus, D. pilus, D. refertus, D. signatus and D. uncus. Features of the basal portion of the dorsal body of the male genitalia are defined and described for the first time, including the basal bar, the connector and the basal plate. A key to the species of the microstictus species-group is included. A mating pair of D. uncus collected in copula is recorded and the female is described. Key words: Pristocerinae, conicus species-group, D. xanthopus, bilaminar paramere Introduction Since Dissomphalus was described by Ashmead (1893), the main diagnostic character for species in this genus was the tergal process. Evans (1954) named the ventral and dorsal laminae as ventral ramus and dorsal body. From Azevedo (1999a) until now, the complexity and variability observed in the genitalia of Dissomphalus have been used to classify species, because they are more precise in delimiting species compared to the tergal processes. Today, Dissomphalus species and some species-groups are diagnosed by particular features in the genitalia. When D. microstictus Evans was described, the main diagnostic character used to identify this species was the second metasomal segment with “a pair of widely spaced very small pits with raised rims, these pits in very shallow, broad depression and flanked by a few setae” (see Evans 1969). Evans, however, did not mention any feature of the genitalia. Azevedo (1999b) reanalyzed the holotype and described the male genitalia of D. microstictus adding to its diagnostic features the latero-apical filament of the ventral ramus of the aedeagus, which was unique among Dissomphalus species known at that time. While analyzing specimens previously identified as D. microstictus, we perceived some structural variations mainly in the dorsal body of the genitalia, which are important to report. After investigating this variation, we came to the conclusion that multiple species were masquerading as D. microstictus. We described 13 new species and defined the microstictus species-group based on the presence of the latero-apical filament of the ventral ramus of aedeagus. Material and methods Material examined: This study is based on examination of Neotropical specimens from the following instituAccepted by J. Pitts: 16 Jul. 2008; published: 18 Aug. 2008 1