PROC. ENTOMOL. SOC. WASH. 119(Special Issue), 2017, pp. 823–842 PHYLOGENY OF THE AGATHIDINAE (HYMENOPTERA: BRACONIDAE) WITH A REVISED TRIBAL CLASSIFICATION AND THE DESCRIPTION OF A NEW GENUS urn:lsid:zoobank.org:pub:313D65AD-A7A0-4BAE-93E3-2A436A719C60 MICHAEL J. SHARKEY AND ERIC G. CHAPMAN Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, 1100 S. Limestone, Lexington, Kentucky, 40546 Email: msharkey@ uky.edu; eric.chapman@uky.edu MJS: urn:lsid:zoobank.org:author:77B8EC3A-442C-4A7A-AF85-A31C27E257F2 EGC: urn:lsid:zoobank.org:author:6DFE2A05-3D5A-4AD8-90AC-02F8DA2DC452 Abstract.—The phylogeny of the Agathidinae is analyzed employing 45 agathidine genera, 172 Agathidinae operational taxonomic units, and sequences from the mito- chondrial gene COI and the nuclear ribosomal gene 28S. The tribal classification is revised; two new tribes are proposed, i.e., Lytopylini and Agathirsini. Mesocoelini n. stat., is included as a tribe of Agathidinae for the first time. The concepts of Earinini and Agathidinini are revised. Biroia Sze ´pligeti, 1900, is synonymized with Mega- lagathis Schulz, 1906 (emendation for Megagathis Krechbaumer 1894). A new genus and species from Colombia, Smithagathis davidsmithi Sharkey are erected. The currently recognized 61 genera of Agathidinae are presented in a list which includes their tribal placement. Biroia Sze ´pligeti, 1900, and its junior synonym Isoptronotum Enderlein, 1920 are synonymized with Megalagathis Schulz, 1906, new synonymies. The species of Biroia are moved to Megalagathis as new combinations. Key Words: Ichneumonoidea, systematics, taxonomy, new tribe DOI: 10.4289/0013-8797.119.Special Issue.823 Agathidinae is a moderately large sub- family the members of which are koino- biont endoparasitoids of lepidopterous larvae. For more general information on agathidines see Sharkey et al. (2006). As of 2005, roughly 1000 species were described (Yu et al., 2005). Although Sharkey (et al. 2006) estimated an addi- tional 2000-3000 undescribed species, the senior author (MJS), based on the number of new species in the following works, now believes that there are a magnitude more undescribed species. Since 2006, many revisions have been conducted, in- cluding: Sharkey and Chapman (2017): 10 new agathidine genera from Thailand; Sharkey and Chapman (2016): Revision of Aerophilus (formerly Lytopylus); Sharkey et al. (2015): Revision of Aphelagathis; Sharkey and Chapman (2015): Revision of