REVISION OF NEARCTIC SPECIES OFACTIAROBINEAU-DESVOIDY (DIPTERA: TACHINIDAE)

Abstract

AbstractEight species of the siphonine genusActiaRobineau-Desvoidy are recognized in the Nearctic Region, including four that are new:A.dasymyiasp.nov. (type-locality 21 mi. east Tuktoyaktuk, North West Territories, Canada),A.dimorphasp.nov. (type-locality Sapelo Island, Georgia, USA),A.radialissp.nov. (type-locality Gatineau Park, Quebec, Canada), andA.sternalissp.nov. (type-locality mi. 51 Dempster Highway, Yukon, Canada). Adults of the eight species are keyed, described, illustrated (heads, wings, and male terminalia), and their distributions mapped. The species are arranged into three species groups: theautumnalis-group with Nearctic membersA.autumnalis(Townsend),A.rufescens(Greene),A.diffidensCurran, andA.dimorphasp.nov.; thelamia-group with Nearctic membersA.interruptaCurran,A.dasymyiasp.nov., andA.radialissp.nov.; and thecrassicornis-group with the single Nearctic memberA.sternalissp.nov. NearcticActiaare inferred to be of relatively recent origin because only theA.autumnalis/A.rufescensspecies pair seems to have speciated within the Nearctic Region.Actia autumnalis/A.rufescens,A.diffidens, andA.dimorphaare each hypothesized to have their closest phylogenetic affinities with Neotropical species, andA.sternalis,A.interrupta,A.dasymyia, and questionablyA.radialisare each hypothesized to have their closest affinities with Palearctic species.