Trieces Townes 1946
Creators: name: Ranjith, A. P.
name: Priyadarsanan, Dharma Rajan
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Trieces

description: Genus Trieces Townes, 1946
Trieces Townes, 1946: 60.
Type species: Exochus texanus Cresson, 1872.
Diagnosis
Eyes glabrous or sparsely setose, slightly emarginated near antennal torulus (Figs 1B, 3B, 5B). Face often wider than long (Figs 1B, 3B, 5B), rarely longer than wide, sometimes narrowing posteriorly (Figs 3B, 5B). Interantennal process distinct, acute (Figs 1B, 3B, 5B). Clypeus transverse, separated from face by shallow transverse impression, apical margin sharp and more or less truncate, weakly convex or slightly concave. Mandible often with upper and lower teeth, rarely lower tooth absent. Frons depressed, without midlongitudinal lamella (Figs 1C, 3C, 5C). Temple not bulged behind eyes in dorsal view (Figs 1C, 3C, 5C). Pronotum evenly convex without impression. Propleuron weakly swollen (Figs 1E, 3E, 5E). Mesonotum without notauli (Figs 1F, 3F, 5D). Scutoscutellar groove small, smooth (Figs 1F, 3F, 5D). Scutellum with distinct lateral carina (Figs 1F, 3F, 5D). Mesopleuron without sternaulus (Figs 1E, 3E, 5E). Epicnemial carina present and complete (Figs 1E, 3E, 5E). Mesopleural suture absent (Figs 1E, 3E, 5E). Metapleuron with or without longitudinal wrinkles and posterior slit (Figs 1E, 3E, 5E). Propodeum with distinct pleural carina and a pair of submedial carinae, posterior transverse carina absent (Figs 2A, 4A, 5F). Fore and mid tarsal claws pectinate, hind tarsal claw simple. Fore wing without areolet (Figs 2B, 4B, 6C). Fore wing vein 1cu-a interstitial to postfurcal (Figs 2B, 4B, 6C). Hind wing vein CU1b absent. Metasomal tergites without laterotergites (Figs 2C, 4D, 6A). First metasomal tergite broad posteriorly with dorsal and dorso-lateral carinae (Figs 2D, 4C, 6B), and rarely with ventro-lateral carina (Fig. 2C). Spiracle of first metasomal tergite at anterior ⅓ rd (Figs 2C, 4D, 6A). Second metasomal tergite with midlongitudinal and lateral carinae (Figs 2D, 4C, 6B). Third metasomal tergite often with complete midlongitudinal carina and lateral carina (Figs 2D, 4C, 6B). Fourth metasomal tergite often without lateral carina (Figs 2C, 4D, 6A). Ovipositor slender apically (Fig. 4D).
Distribution
Though Yu et al. (2016) listed this as a cosmopolitan genus, there were no described species of this genus so far from the Indomalayan region.
Biology
Larval-pupal endoparasitoids of Lepidoptera particularly Tortricidae and Yponomeutidae (Gauld et al. 2002; Broad et al. 2018).
Key to separate Trieces Townes, 1946 from Chorinaeus Holmgren, 1858
1. Mesopleuron with mesopleural suture (Fig. 7A, C); lateral longitudinal carina only present on metasomal tergite 1 and base of second metasomal tergite (Fig. 7A, D–F); pronotum with dorsal longitudinal depression (Fig. 7B) (weak in C. brevicalcar Thomson, 1887) ........... Chorinaeus Holmgren, 1858
– Mesopleuron without mesopleural suture (Figs 1E, 3E, 5E); lateral longitudinal carina present on metasomal tergites 1–3 (absent in T. ranjithi) (Figs 2D, 4C, 6B); pronotum without dorsal longitudinal depression (weakly present in T. flabenis Gauld & Sithole, 2002) .................. Trieces Townes, 1946
Key to the Palearctic and Oriental species of Trieces Townes, 1946 (onitis group)
1. Metapleuron without posterior slit-like depression ............................... other Trieces species groups
– Metapleuron with distinct posterior slit-like depression (Figs 1E, 3E, 5E) ........................................ ........................................................................................................................2 (Trieces onitis group)
2. Occipital carina absent; ocellar area elevated; face black; metapleuron glabrous or sparsely setose ........................................................................................................................................................... 3
– Occipital carina present (Figs 1C, 3C, 5C); ocellar area flat; face yellow or with brownish patches (Figs 1B, 3B, 5B); metapleuron densely or moderately setose (Figs 1E, 3E, 5E) ........................... 4
3. Face as wide as long; antenna with 18–19 flagellomeres; first flagellomere 1.3× as long as wide [Japan and Russia] ........................................................................... Trieces hokkaidensis Kusigemati, 1967
– Face wider than long; antenna with 22–23 flagellomeres; first flagellomere 1.6 × as long as wide [Japan and Russia] ................................................................ Trieces mandiblaris Kusigemati, 1971
4. Face completely yellow without brown patches (Fig. 1B); mandible with only upper tooth (Fig. 1D); antenna with 19 flagellomeres; first metasomal tergite with distinct wide, smooth longitudinal groove laterally (Fig. 2C); fore wing vein 1cu-a interstitial (Fig. 2B); temple posterior half yellow; mandible, scape and pedicel yellowish brown [India] ..................................................... Trieces irwini sp. nov.
– Face yellow with midlongitudinal brown patches or entirely black with yellow spot antero-medially (Figs 3B, 5B); mandible with upper and lower teeth; antenna with 20–33 flagellomeres; first metasomal tergite without longitudinal groove laterally, if present then indistinct (Figs 4D, 6A); fore wing vein 1cu-a postfurcal (Figs 4B, 6C); temple posterior half black; mandible, scape and pedicel dark brown ................................................................................................................................................ 5
5. Mesopleuron without longitudinal wrinkles posteriorly; metapleuron densely setose; propleuron densely setose; area superomedia smooth [Japan, Russia and South Korea] ..................................... .................................................................................................... Trieces homonae Kusigemati, 1967
– Mesopleuron with longitudinal wrinkles posteriorly (Figs 3E, 5E); metapleuron only posteriorly setose, rest glabrous (Figs 3E, 5E); propleuron glabrous (Figs 3E, 5E); area superomedia with wrinkles (Figs 4A, 5F) ..................................................................................................................................... 6
6. Temple longer than transverse diameter of eye in lateral view; antenna with 33 flagellomeres; face black with yellow spot antero-medially; midlongitudinal carina of third metasomal tergite 0.7 × as long as tergite [South Korea] .................................................... Trieces koreanus Choi & Lee, 2016
– Temple shorter than transverse diameter of eye in lateral view (Figs 3E, 5E); antenna with 20–23 flagellomeres; face yellow with brown longitudinal patch medially; midlongitudinal carina of third metasomal tergite 0.5 × as long as tergite (Figs 4C, 6B) .................................................................. 7
7. Metapleural slit short, isolated (Fig. 3E); metapleuron longitudinally striated (Fig. 3E); mesopleuron and propodeum distantly punctate (Figs 3E, 4A); submedial carinae of first metasomal tergite parallel posteriorly (Fig. 4C) [India] ......................................................................... Trieces isolatus sp. nov.
– Metapleural slit long, curved (Fig. 5E); metapleuron basal half smooth (Fig. 5E); mesopleuron and propodeum closely punctate (Figs 5E, F); submedial carinae of first metasomal tergite narrowing posteriorly (Fig. 6B) [India] ...................................................................... Trieces orientalis sp. nov.
description: Published as part of Ranjith, A. P. & Priyadarsanan, Dharma Rajan, 2022, First description of the metopiine genus Trieces Townes, 1946 (Hymenoptera: Ichneumonidae) from the Indomalayan region with three new species from India, pp. 1-17 in European Journal of Taxonomy 794 (1) on pages 3-4, DOI: 10.5852/ejt.2022.794.1649, http://zenodo.org/record/6038076