A revision of the genus Trogus (Hymenoptera: Ichneumonidae, Ichneumoninae)

The ichneumonine genus Trogus is revised, with descriptions, diagnoses and a key provided for the twelve recognized species. The species treated herein are: T. crustosus Wahl, sp.n.; T. edwardsii Cresson (= T. fletcherii Harrington, Macrojoppa californica Cresson syn.n.); T. flavipennis Cresson; T. fulvipes Cresson (= Trogus apicatus Davis); T. ixcuinae Wahl, sp.n.; T. koreensis Wahl, sp.n.; T. lapidator (Fabricius) (= Ichneumon coerulator Weber, Ichneumon coerulator Fabricius, Ichneumon saxator Gravenhorst, Trogus fuscipennis Gravenhorst syn.n., Psilomastax violaceus Mocsáry syn.n., Trogus cyaneipennis Costa syn.n., Psilomastax cyaneus Kriechbaumer syn.n., Trogus lapidator romani Uchida syn.n., Trogus lapidator brevicaudae Heinrich syn.n., Trogus lapidator panzeri Carlson syn.n.); T. pennator (Fabricius); T. picadoae Wahl, sp.n.; T. pompeji (Kriechbaumer); T. thoracicus (Cresson); T. vulpinus Gravenhorst (= T. exesorius Brullé, Dinotomus vulpinus var. nigrithorax Strand syn.n., T. pennator ssp. argutus Heinrich syn.n.). A critical review and examination of preserved host material confirmed that Trogus specializes on the Papilionidae. Finer patterned host use within the genus is attributed to the chemistry of hosts and their food plants. Several Trogus species are polyphagous within the Papilionidae with substantial overlap amongst host ranges, indicating that ecological opportunism rather than host-parasite coevolution has most influenced the evolution of the genus.