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Species Trogus pennator

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Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon ("Parasitica" - Parasitoid Wasps)
Superfamily Ichneumonoidea (Braconid and Ichneumonid Wasps)
Family Ichneumonidae (Ichneumonid Wasps)
Subfamily Ichneumoninae
Tribe Ichneumonini
No Taxon (Trogus Genus Group)
Genus Trogus
Species pennator (Trogus pennator)
Synonyms and other taxonomic changes
Trogus pennator (Fabricius, 1793)
Explanation of Names
From Latin penna a feather, or a wing (1).
circa 19 mm length, 33 mm wingspan (guide photo measurements)
T. pennator is an eastern, red species. True T. pennator is identified by the following combination: low, rounded scutellum (generally); supra-antennal area with two low ridges medially (rarely developed into denticles); and the fifth tergite of the female lacking prominent ridge. Both T. pennator and T. vulpinus share having long setae on tergites 2–6.(2)

Note: Those with a high, conical scutellum generally correspond to T. vulpinus.
eastern US and extreme southeastern Canada
Known larval hosts include: Eurytides marcellus, Papilio palamedes, P. polyxenes, and P. troilus.(2) It is worth noting that all of the above species are also parasitized by T. vulpinus.

Note: This species is not known to be reared from P. glaucus, P. brevicauda, or P. canadensis. Eastern red species reared from these hosts may correspond instead to T. vulpinus.
Life Cycle
Trogus pennator is a parasitoid of swallowtail butterflies (Papilionidae), ovipositing in the caterpillars.

The solitary larva develops inside the caterpillar, allowing it to pupate before killing it. After metamorphosing, the adult wasp chews an irregular hole in the chrysalis to escape.
Perhaps a mimic of well-armed spider wasps, such as Tachypompilus ferrugineus:
See Also
T. edwardsii is a western species and does not overlap with T. pennator or T. vulpinus. It is further recognized by the following combination: scutellum elevated and conical; supra-antennal area with two developed denticles medially; transverse rugae on the petiole; tergites 2–6 with short setae; tergite 3 finely punctured.(2)

T. vulpinus is an eastern species that overlaps with T. pennator. It is separated by the following combination: scutellum elevated and conical (versus low and rounded); supra-antennal area with two developed denticles medially (versus ridges rarely developed into denticles); and fifth tergite with a prominent ridge separating the dorsal and lateral surfaces (versus no ridge throughout).(2)
Print References
Borror, entry for penna (1)
Eaton and Kaufman, pp. 328-329 (genus Trogus) (3)
Marshall, photo 545.9 (4)
Sime, Karen. The natural history of the parasitic wasp Trogus pennator (Hymenoptera: Ichneumonidae): Host‐finding behaviour and a possible host countermeasure. Journal of Natural History, Volume 39, Number 17, 2005 , pp. 1367-1380(14) (abstract).
Internet References of this species emerging from swallowtail pupa
Works Cited
1.Dictionary of Word Roots and Combining Forms
Donald J. Borror. 1960. Mayfield Publishing Company.
2.A revision of the genus Trogus (Hymenoptera: Ichneumonidae, Ichneumoninae)
David B Wahl. and Karen R. Sime. 2006. Systematic Entomology 31(4): 584 - 610.
3.Kaufman Field Guide to Insects of North America
Eric Eaton, Kenn Kaufman. 2006. Houghton Mifflin.
4.Insects: Their Natural History And Diversity: With a Photographic Guide to Insects of Eastern North America
Stephen A. Marshall. 2006. Firefly Books Ltd.