Tritoxa Loew 1873
Creators: name: Sinclair, Bradley J.
name: Macleod, Alyssa M.
name: Wheeler, Terry A.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Ulidiidae
Tritoxa

description: Key to the species of Tritoxa
(modified from Steyskal (1967))
1 Thorax and abdomen dark brown to black (Fig. 1), wings with dark brown to black background (Fig. 9); crossvein dm-m sinuate................................................................................. T. flexa (Wiedemann)
- Thorax and abdomen reddish-brown to brown (Fig. 2), wings with brown background (Figs 6–8, 10–13); crossvein dm-m straight to slightly sinuate or angulate..................................................................... 2
2 Crossvein dm-m straight or slightly sinuate (Figs 6–8, 10, 13); silvery parafrontal microtrichose stripe very narrow, only immediately adjacent to eye (Fig. 3)........................................................................ 3
- Crossvein dm-m angulate, or slightly angulate (Figs 11, 12); silvery parafrontal microtrichose stripe broad, surrounding bases of orbital setae (Figs 4, 5)............................................................................... 7
3 Discal and subapical hyaline crossbands arcuate and parallel (Fig. 10); subapical hyaline crossband attaining costa basad of crossvein r-m............................................................................ T. incurva Loew
- Discal and subapical hyaline crossbands arcuate or straight (Figs 6–8, 13); subapical hyaline crossband essentially straight, attaining costa apicad of crossvein r-m.................................................................... 4
4 Discal hyaline crossband reaching posterior wing margin, or at least extending beyond cell dm (Fig. 13); small hyaline spot in costal cell distal to humeral crossvein; silvery parafrontal microtrichia stripe distinct, extending nearly half distance from eye margin to orbital setae......................................................................... Tritoxa sp.
- Discal hyaline crossband not extending beyond cell dm (Figs 6–8); costal cell distal to humeral crossvein dark, without hyaline spot; silvery parafrontal microtrichia stripe narrow, extending less than one-third distance from eye margin to orbital setae.. 5
5 Discal hyaline crossband ending in or very close to posterior distal corner of cell dm, generally tapered (Fig. 8); inner surstylus with row of 5–8 strong prensisetae; outer surstylus arched mesally (Fig. 17)........................ T. decipiens sp. nov.
- Discal hyaline crossband ending distant to posterior distal corner of cell dm and usually wide posteriorly (Figs 6, 7); inner surstylus with prensisetae widely separated or in tight cluster; outer surstylus straight or arched (Figs 14, 16)............ 6
6 Inner surstylus with 3–4 strong, separated prensisetae; outer surstylus straight (Fig. 16); phallus very long, comprising some 4–5 loops; discal hyaline crossband long, extending to opposite crossvein r-m (Fig. 7).................. T. cuneata Loew
- Inner surstylus with straight row of 4–5 thick prensisetae in tight cluster, decreasing in size with largest adjacent to outer surstylus (Fig. 14); outer surstylus arched (Fig. 14); phallus much shorter than typical of genus, comprising 2 loops (Fig. 15); discal hyaline crossband shorter, not reaching opposite r-m crossvein (Fig. 6).......................... T. californica sp. nov.
7 Crossvein dm-m with stump vein (Fig. 12); silvery parafrontal microtrichia stripe extending 1/4 to 1/3 distance from eye margin to midfrons (Fig. 5); discal hyaline crossband continuous from R 1 to posterior wing margin (Fig. 12); anepisternum shiny............................................................................................. T. ra Harriot
- Crossvein dm-m usually without stump vein (Fig. 11); silvery parafrontal microtrichia stripe extending halfway from eye margin to midfrons (Fig. 4); discal hyaline crossband disjunct along R 2+3 (Fig. 11); anepisternum densely clothed in yellow microtrichia............................................................................. T. pollinosa Cole
description: Published as part of Sinclair, Bradley J., Macleod, Alyssa M. & Wheeler, Terry A., 2021, Revision of the Nearctic genus Tritoxa Loew (Diptera: Ulidiidae), pp. 359-379 in Zootaxa 4920 (3) on page 361, DOI: 10.11646/zootaxa.4920.3.3, http://zenodo.org/record/4478080