Genus Argentinomyia Lynch-Arribálzaga, 1891

Argentinomyia Lynch-Arribálzaga, 1891: 199 [1892: 40]. Type species, Argentinomyia testaceipes Lynch-Arribálzaga by monotypy. Refs.: Enderlein, 1938: 201 (catalog citation); Fluke, 1945: 1–30 (key, reference, description, distribution); Fluke, 1957: 261–279 (study of male genitalia); Vockeroth 1969: 138 (catalog citation); Thompson et al. 1976: 39, 46 (catalog citation); Thompson, 1981: 105 (desc. Notes, distribution); Thompson, 1999a: 325, 327 (citation on key) and 338 (notes and status); Thompson et al. 2010: 767 (Fig. 22, lateral view of Argentinomyia sp., Fig. 23, frontal view of Argentinomyia rugosonasa), 776 and 779 (key to Argentinomyia), 786 (distribution and diversity).

= Rhysops Williston, 1907: 2 . Type species, Melanostoma rugosonasus Williston by subsequent designation of Coquillett (1910: 601). Proposed for “ Melanostoma scitulum, rugonasus, melanocerum ”.

= Braziliana Curran, 1925: 252 . Type species, Melanostoma longicornis Williston by original designation. = Pipiza longicornis Walker

= Allograptina Enderlein, 1938: 226 . Type species, Argentinomyia octomaculata Enderlein by original designation.

= Aristosyrphus Curran 1941: 252 (Erroneous synonym and treated as a subgenus by Thompson et al. 1976: 60; catalog citation).

Generic diagnosis (Adapted from Lynch-Arribálzaga, 1891; Fluke, 1945, 1957; Thompson 1999a; Huo 2014; Thompson & Skevington 2014; Mengual 2020). Small to medium-sized flies. Length: 4.1–12 mm. Head: Face black, straight in profile, slightly produced forward ventrally; with facial tubercle weak, usually with transversal grooves dorsally along tubercle (Figs 4C, 64A, D, 71A, D, 93A, D; Thompson et al. 2010: Fig. 23), face sometimes uniformly pollinose, rarely with shine (bare) punctuate maculae; gena narrow; frontal triangle not swollen, female frontal triangle generally with a pollinose pattern on vertex (Fig. 4) varying from a complete transversal black fascia (Figs 4C, F and G) or two brownish-black rounded maculae (Fig. 4B) or non (Fig. 4H); eye bare, generally holoptic in male; antennal pits separated; antennal bases slightly anterior to the oral margin; oral opening less than twice as long as broad; antenna generally long, with scape longer than broad, about twice as long as pedicel or longer than pedicel and basoflagellomere together, basoflagellomere oval or slightly elongate, never more than twice as long as broad, generally longer than pedicel; arista short, about as long as the scape, dorso-basal (Figs 4A–L). Thorax: Black, postpronotum (humerus) bare; notopleuron with a distinct tubercle; mesonotum generally black to brown. Scutum black, usually shining or subshining, covered with green coppery to blue pollen, hairs on thorax blackish or yellowish (Fig. 6A–C). Scutellum black, subtriangular, rounded apex, with three to four transversal rugose lines, sometimes with longer black setae on posterior margin (Fig. 6K); subscutellar fringe complete; pleurae usually lightly pollinose; metathoracic pile patch absent; anterior anepisternum bare; katepisternal pile patches broadly separated throughout; metasternum bare and fully developed (Fig. 3B); postmetacoxal bridge incomplete; male legs, simple, slender, without bristles, pile tufts or modified hairs, mesocoxa without pile posteromedially on apical angle; plumula simple, short. Wing: Hyaline, sometimes with a transverse brown-tinted band on anterior half (Fig. 8), membrane entirely microtrichose or partially bare on basal portion of wing, alula broad, microtrichose, about as wide as cell cua; vein M1 at most weakly sinuate; vein R usually straight or nearly so. Abdomen: Dark-colored, often with variously shaped light-colored yellow, orange to silvery-grey pollinose paired maculae, triangular to quadrate or oval on 2 nd to 4 th terga, sometimes including a small macula on 5 th tergum. Male Abdomen: Nearly parallel-sided, as broad as scutum on male, slightly oval on female, as broad as or broader than thorax, segments more or less quadrate; maculae on tergum vary in size and shape between tergites, with light-colored yellow, orange to silvery-grey pollinose maculae; triangular to quadrate markings on 2 nd to 4 th terga, the 2 nd tergum sometimes two times longer than broad, generally with abundant lateral long yellow pile, without premarginal sulcus (Fig. 8D–F). Female abdomen: Oval, tergum 5 th 1/3 of the length of tergum 4th; tergum 6 th 1/4 of the length of tergum 5 th; tergum seventh visible without dissection; terga 6 th and seventh rectangular; tergum 6 th as long as wide; tergum seventh longer than wide; tergum seventh with a pair of lateral and one medial, apical extensions, sparse pile restricted to unsclerotized apical areas; tergum eighth longer than wide, with a wide median sclerotized band, with basal and apical concavities, sparse pile restricted to apical half (Figs 5A–C and 8B, C, E and G). Male genitalia: Cercus slightly elongated, widened apically; surstyli very variable in shape, short, no more than two times longer than broad, narrow basally, generally widened apically, but never bilobed (non-forked); lingula absent; phallus (aedeagus) simple, unsegmented, generally swollen ventrally towards the apex; apex of hypandrium (superior lobes) variable, triangular or squarish in shape, but never sickle-shaped; ejaculatory apodeme cylindrical. Female genitalia: Epiproct as pair of oval sclerotizations, pilose, apodeme slightly longer than the epiproct; hypoproct triangular, pilose. Cerci oval and less sclerotized, pilose, positioned ventrolaterally to the epiproct. Spermatheca globose (Figs 5A–C).

Biology. The biology, life cycle and habitat preferences of immature stages of Argentinomyia remain unknown. Even though, Lima (1946) described the new species A. berthae, raised from larvae feeding on egg clutches of the glass frogs, Vitreorana eurygnatha (Lutz, 1925) ( Anura: Centrolenidae), species associated with forest streams on primary forests of southeastern Brazil. Despite the frog-fly interactions is common (see Villa 1977, 1984), the unexpected record of immature stages of Argentinomyia feeding on this centrolenid frog needs to be corroborated and more likely, they could be predators of soft-bodies arthropods as are all other known melanostomine genera [Bacchini and Melanostomini]. For its part, Dr. Wirth in 1958 collected a pupa of A. longicornis on a leaf of Chamaedorea elegans Mart. (Arecaceae), probably the host plant of its prey, however, no specific information was associated with the label data.

Adults of Argentinomyia are often observed visiting flowers during the sunny days in pristine ecosystems such as Tropical montane cloud forests, high Andean forests and Páramo (high mountain wet tropical habitats unique to the Neotropics). Adults employ hill-topping as a mating aggregation system, where males are sometimes found hovering as low as ca. 60 cm above the ground, but most at elevations of about 1.5 m to 2.5 m, even up to 6 m or more in high isolated areas (for a complete definition of hill-topping; see Waldbauer 1990; Skevington 2008 and Skevington et al. 2019). In this mating behavior, several males fly in lek formation (lineal aggregation), during which males attempt to control territories within a small area to which females are attracted looking for flowers, oviposition sites and resources for larval development (Alcock 1987), allowing her to select which male is more suitable to copulate.

Label data and field observations show that adults of Argentinomyia visit flowers of Ageratina tinifolia (Kunth) R.M. King & H. Rob., Baccharis sp., Barkleyanthus salicifolius (Kunth) H. Rob. & Brettell, Bidens pilosa Linnaeus, Dahlia imperialis Roezl ex Ortgies, Diplostephium rosmarinifolium (Benth.) Wedd., Espeletia occidentalis A.C. Sm., Libanothamnus humbertii (Cuatrec.) Cuatrec., Pentacalia ledifolia (Kunth) Cuatrec., Pentacalia trianae (Klatt) Cuatrec and “Dandelion” Taraxacum officinale Weber ex F. H. Wigg (Asteraceae), Bursera sp. (Burseraceae), Trema sp. (Cannabaceae), Clusia cf. brachycarpa Cuatrec. (Clusiaceae), Gaiadendron punctatum (Ruiz & Pav.) G. Don (Loranthaceae), Tibouchina mollis (Bonpl.) Cogn. (Melastomataceae), Acca sellowiana (O. Berg) Burret (Myrtaceae), Fuchsia arborescens Sims (Onagraceae), Passiflora edulis Sims (Passifloraceae), Coffea arabica Linnaeus (Rubiaceae), Zanthoxylum sp. (Rutaceae), Buddleja coriacea J. Rémy (Scrophulariaceae), Senecio oerestedianus Bent (Senecionaceae) and Aloysia triphylla Paláu ( Verbenaceae). Most of these plants are distributed at elevations above 2000 m. In the Galápagos Islands, Argentinomyia agonis has been recorded visiting flowers of Bursera sp., Trema sp. and Zanthox sp., as well as the endemic species Miconia robinsoniana Cogn (Melastomataceae) which is considered Endangered within the archipelago (Sinclair & Peck 2002, 2005; Boada 2005; Sinclair et al. 2016; Sinclair 2017). In particular, A. longicornis has been documented visiting flowers of Avocado, Persea americana Mill. Cv. Hass (Lauraceae) in Colombia (Carabalí-Banguero et al. 2018). Finally, Argentinomyia altissima, A. browni, A. opaca and A. rex have an affinity for Páramo habitats in Colombia (Ángel et al. 2021; Montoya et al. 2021).

Distribution. In total 1720 specimens were studied, revealing that the 47 species of Argentinomyia are distributed in 18 Neotropical countries, 65 states and 143 localities. Argentinomyia is relatively well-collected with a fairly extensive distribution ranging from the northernmost population at 23,264 257, -106,426046 in northwest Mexico and the southernmost found at -34,635771, -60,464900 in southeast Argentina (Figs 88–96). Members of the genus span several habitats from low-elevation (0 meters above sea level) to high-elevation (4100 m), but most specimens have been collected in grassland areas as well as primary and secondary-growth forests between 2700 to 3500 m. In Central America, 22 species are recorded, of which 12 are considered endemic and distributed in the ecoregions Moist and Pine Oak Forests (Figs 89, 96). In the Caribbean Islands, A. aurifacies sp. nov., A. jamaicensis sp. nov., A. praeusta and A. taina sp. nov. are range-restricted to the Dry and Moist Forest, meanwhile, in the Galápagos Islands, A. agonis is exclusive to Xeric scrublands Forest (Fig. 95). In southeastern South America, 14 species (two endemic: A. norrbomi sp. nov. and A. plaumanni sp. nov. restricted to a small relict of Atlantic Forest) inhabit the Moist, Savanna and Coastal Forest (Figs 91–94). In Tropical Andes, 24 species are known (15 endemics), most frequently encountered throughout Andean forests and tropical alpine ecosystems (Páramos), in the ecoregions Montane and Moist Forest. In this region, nine out of the 16 newly described species ( A. belmira sp. nov., A. humboldti sp. nov., A. ivani sp. nov., A. occidentalis sp. nov., A. serendipia sp. nov., A. spinifemorata sp. nov., A. teresae sp. nov., A. transversalis sp. nov., A. tropandeana sp. nov.) are restricted to a single isolated island (top hills) in the mountainous archipelago (Figs 90–91) (Myers et al. 2000), areas that harbor the highest diversity and numbers of endemic Syrphidae species in the Neotropics (Thompson et al. 1976; Thompson 1999a; Montoya et al. 2012; Morales et al. 2013; Montoya 2016; Montoya et al. 2017; Evenhuis & Pape 2020; Montoya & Wolff 2020; Montoya et al. 2021) (Fig. 95). Argentinomyia longicornis (Fig. 91C) and A. crenulata (Fig. 91D) are widely distributed, occurring from Northwestern Central to Southeastern South America, meanwhile, A. luculenta (Fig. 91A) and A. tropica (Fig. 91B) are widespread from Northwestern to Southeastern South America. Finally, even though long-term and thorough sampling effort has been done, the genus is absent in the Chilean subregion and has not been registered in Surinam (Thompson 1999a; Reemer 2010; Thompson et al. 2010; Barahona-Segovia et al. 2021).

Identification key to the species of Argentinomyia

The last key of Fluke (1945) included only 19 valid species. A new key to the known species of Argentinomyia is provided based on characters published by Fluke (1945, 1957) and Thompson (1999a; 2006), including some modifications and couplet´s order to distinguish them from the sixteen new species. Argentinomyia scitula is not included in the key due to its doubtful validity, since the only known specimen is a teneral, headless, with no additional males found in good condition for dissection and deep examination.

1. Basoflagellomere large, slightly oval and apically rounded (SNLSA Figs 1C, F); face with a well-rounded tubercle, never with transversal grooves dorsally along tubercle or broadly punctuate (SNLSA Figs 1A, D); scutellum with a deep groove next to the rim (emarginate) (SNLSA Figs 5F, 1B, 1E, 12D); metacoxa with pile posteromedial on the apical angle (SNLSA Fig. 12C); abdomen elongated, with large markings on terga, sometimes with a transverse fascia on 3 rd or with a pair of small maculae in the basal corners of the 5 th tergum (SNLSA Figs 1B, E).............................................................................................. larger species of Argentinomyia (in Montoya & Wolff 2020, not treated here)

- Basoflagellomere oval or slightly elongated (MCAD Fig. 22); face usually with transversal grooves dorsally along tubercle (MCAD Fig. 23) and shine (bare) punctuate maculae laterally; scutellum without a deep groove next to the rim; metacoxa without a pile tuft at the posteromedial apical angle; abdomen slightly spatulate, oval or with parallel sides, with triangular to quadrate or oval markings.............................................................................. 2

2. Antenna elongated, scape about as long as or longer than pedicel and basoflagellomere combined, scape always twice as long as pedicel (Figs 1A–B, 4J, K, L, 6B, C, 26A, 55A, D, 81A, D)................................................. 3

- Antenna short, scape shorter than pedicel and basoflagellomere combined (Figs 2A, 4D, F, G, I)....................... 7

3. Face with seven or eight shallows, transverse grooves above tubercle; sides of the face with a thin white line of pollen; pedicel and basoflagellomere about equal in length; wings with two short, narrow, transverse brown bands near the middle of the anterior half (Fig. 8A); metafemur and protibia black (Figs 7A, 26A–F); male genitalia: surstylus in lateral view (Fig. 27A) with dorsal and ventral margins approximately of the same width in the whole length; hypandrium in ventral view (Fig. 27C) narrowed laterally towards the apex; aedeagal lobe in ventral view (Fig. 27C) circular, apex rounded [Bolivia, Colombia, Costa Rica, Guatemala, Guatemala, Mexico, Nicaragua and Perú].................. Argentinomyia crenulata (Williston, 1891)

- Face at most with one transversal groove above tubercle, never with seven or eight; facial pollinose pattern variable; basoflagellomere twice as long as pedicel; wings with at most only a faint brownish clouding on anterior cross-vein, never with medial brown fascia; metafemur yellow basally............................................................. 4

4. Sides of the face evenly white pubescent, not punctuate; female frontal triangle wide, male dichoptic; metatibia yellow [Southeastern South America species].................................................................... 5

- Sides of face punctuate; female frontal triangle narrow, male eyes holoptic; metatibia brown......................... 6

5. Face with a low tubercle and with no prominent depressions; frontal prominence greatly produced; abdomen metallic, without orange maculae (Figs 1A–B, 81A–F); male genitalia: surstylus in lateral view (Fig. 82A) with dorsal and ventral margins approximately of the same width in the whole length; apex of hypandrium (superior lobes) short, as long as wide (Figs 82A and C) [ Argentina, Brazil and Perú]................................. Argentinomyia testaceipes Lynch-Arribálzaga, 1891

- Face with four distinct transverse grooves above tubercle; frontal prominence not greatly produced (Figs 4J, K); abdomen with orange maculae (Figs 9B, 10A, 55A–F); male genitalia: surstylus in lateral view (Fig. 56A) with dorsal margin slightly concave and ventral margin slightly convex; apex of hypandrium (superior lobes) elongated, about 3× as long as wide (Figs 56A and C) [Brazil]........................................................... Argentinomyia norrbomi Montoya sp. nov.

6. Male without maculae on 4 th tegum (Figs 44B, 46E); male frontal triangle broad; mesotarsus with three apical tarsomeres black (Fig. 6B); scutum greyish pollinose and pilose; female frontal triangle with two rounded maculae of brown pollen (Figs 2B–C, 4B, L, 44D and 46A–B); male genitalia: surstylus in lateral view (Fig. 45A) with dorsal and ventral margins approximately of the same width in the whole length; hypandrium in ventral view (Fig. 45C) narrowed laterally towards the apex; aedeagal lobe in ventral view (Fig. 45C) with acute apex [ Argentina, Brazil, Colombia, Costa Rica, Ecuador, Guatemala, Mexico, Panam, Paraguay, Per and Trinidad and Tobago].................................. Argentinomyia longicornis (Walker, 1836)

- Male with large basolateral orange maculae on 4 th tergum; frontal triangle small; mesotarsus orange; scutum golden pollinose and pilose (female unknown) [Costa Rica and Nicaragua].................................... Argentinomyia CR-19

7. Face usually vertical or perpendicular, never produced downward, generally with distinct transverse grooves above tubercle or very weak ones (Fig. 4B–G, I); female front with a pollinose pattern varying from a complete transversal black fascia (Figs 4C, F and G), two brownish-black rounded maculae (Fig. 4B) or with a medial white pollinose vitta (Fig. 4D); scutellum pile usually as short or shorter than marginal pile (Fig. 6H–I); 2 nd tergum with a pair of yellow maculae varying from widening (Fig. 8C) to narrow elongate (Fig. 9B–C, E–G, 47B, E, 86B, E) or black metallic, both restricted to the lateral margin of the segment (Fig. 9D) or non...................................................................................... 8

- Face may be protruding but very little produced downward, never with transverse grooves above tubercle (Fig. 4H); female front without a pollinose pattern (Fig. 4H), never with a complete transversal black fascia or two brownish-black rounded maculae; scutellar pile generally as long or longer than marginal bristles (Fig. 6K); 2 nd tergum with a pair of maculae varying from narrow elongate yellow maculae (Fig. 6A) to black metallic maculae (Figs 37B, E, 59B, E), both restricted to the lateral margin of the segment [Tropical Andes highland species]..................................................... 44

8. 1 st metatarsomeres black or dark brown, contrasting with the yellow color of the rest other tarsal segments (Fig. 6C)...... 9

- 1 st metatarsomeres yellow or orange, usually not contrasting with the yellow color of the rest other tarsal segments....... 11

9. 2 nd tergum with a prominent transversal fascia (Figs 83A–D) (male unknown) [Colombia and Bolivia]................................................................................ Argentinomyia transversalis Montoya sp. nov.

- 2 nd tergum with a different maculate pattern (Figs 9E, 16B, C, E, F, 35B, C)..................................... 10

10. 3 to 4 rd th terga almost entirely yellow, with a pair of wider yellow maculae from the base to the apical margin of the segment (Figs 9E, 16B, C, E, F); male genitalia: hypandrium in ventral view (Fig. 17C) narrowed laterally towards the apex [Colombia]... Argentinomyia belmira Montoya & Wolff sp. nov.

- 3 to 4 rd th terga with a pair of rectangular yellow maculae extending from the base to the apical 2/3 of the segment length, apically rounded and reaching the lateral margin (Figs 35B, C); male genitalia: hypandrium in ventral view (Fig. 36C) expanded laterally towards the apex (Female unknown) [Colombia]....................... Argentinomyia ivani Montoya sp. nov.

11. Facial pubescence punctuate (Figs 30A, D); abdomen with oblique maculae, male with a pair on 3 rd tergum, female with a pair on 2 nd and 3 rd terga (Figs 30B, E); male genitalia: surstylus in lateral view (Fig. 31A) with dorsal margin slightly concave and ventral margin slightly convex; hypandrium in ventral view (Fig. 31C) expanded laterally towards the apex; aedeagal lobe in ventral view (Fig. 31C) circular, apex rounded [ Argentina, Brazil, Colombia, Per and Venezuela]............................................................................................ Argentinomyia fastigata (Fluke, 1945) [Note: The coloration of pro- and mesofemora can vary from black or at least mostly dark brown to extensively yellow, see remark discussion under the species redescription]

- Facial pubescence not punctuate, other character combination variable.......................................... 12

12. Facial tubercle, scutellum and pleuron partially yellow in ground color (middle region of anepimeron, dorsal surface of katepisternum, katatergum, anatergum and postalar callus) yellow-golden pilose and pollinose in these areas; wing bare basally.............................................................................................. .................................................................................................. 13

- Facial tubercle, scutellum and pleuron black; other characters variables......................................... 15

13. Facial tubercle yellow; calypter wholly brown; all coxae yellow; abdomen with a pair of long, apically rounded oblique maculae on 2 nd to 4 th terga (Thompson 1999a: 375, Figs 13–15) (Male unknown) [Mexico]................................................................................................. Argentinomyia octomaculata (Enderlein, 1938)

- Facial tubercle brown; calypter wholly, yellowish; all coxae brown; abdomen with a pair of long, apically rounded rectangular to triangular maculae on 2 nd to 4 th terga................................................................... 14

14. Face white pilose and pollinose [Costa Rica].............................................. Argentinomyia CR-21

- Face golden pilose and pollinose (Figs 34A–C) (male unknown) [Colombia and Ecuador]...................................................................................... Argentinomyia humboldti Montoya & Wolff sp. nov.

15. Face with four or more distinct and deep transverse grooves above tubercle (Figs 2A, 4C, I) [Central America]......... 16

- Face without defined transverse grooves or with only two or three very weak ones or even none (Figs 2B, 4C, B, D–G, I–L). ................................................................................................. 19

16. 2 nd tergum rectangular, distinctly longer than broad; 3 rd to 4 th terga with basal transverse fasciae [Costa Rica]............................................................................................... Argentinomyia CR-11

- 2 nd tergum square-like, broader than long; 3 rd to 4 th terga without maculae....................................... 17

17. Face with at least five transverse grooves (Figs 2A, 4C, 69A, C, D, F); wing hyaline (Fig. 69); abdomen with metallic maculae (Figs 8D, 69A–F, 65 D-E); male genitalia: surstylus in lateral view (Fig. 70A) triangular-like [Costa Rica and Mexico]...................................................................... Argentinomyia rugosonasa (Williston, 1891)

- Face with no more than four and usually with two shallow grooves or less; wing lightly brown pigmented anteriorly; abdomen with a pair of large quadrate yellow maculae on 2 nd tergum................................................... 18

18. Protibia black (Figs 6H, 8C) [Mexico].................................................... Argentinomyia CR-18

- Protibia yellow on basal 1/3 (Figs 6I, 71A–F); male genitalia: surstylus in lateral view (Fig. 72A) with dorsal margin slightly concave and ventral margin slightly convex [Guatemala, Mexico]................ Argentinomyia sagoti Montoya sp. nov.

19. Pro- and mesofemora orange-yellow..................................................................... 20

- Pro- and mesofemora black or at least mostly dark brown.................................................... 33

20. Facial pubescence golden and very thick, frontal triangle yellow pilose (Figs 32A, D); abdomen with three pairs of yellow vittae on 2 nd to 4 th terga of male and four pairs on 2 nd to 5 th terga of female; metafemur black, except only yellow on basal 1/4 (Figs 32B, E); male genitalia: surstylus in lateral view (Fig. 33A) with dorsal and ventral margins approximately of the same width in the whole length, elongated, at least two times longer than broad; hypandrium in ventral view (Fig. 33C) narrowed laterally towards the apex; aedeagal lobe in ventral view (Fig. 33C) with acute apex [ Argentina, Colombia, Ecuador and Perú]............................................................................. Argentinomyia festiva (Fluke, 1945)

- Facial pile thinner and more whitish, frontal triangle black pilose; abdomen with a different maculate pattern, other character combinations variable................................................................................ 21

21. Metafemur swollen, with ventral spines (Figs 7D, 76A–E) (male unknown) [Colombia]............................................................................................ Argentinomyia spinifemorata Montoya sp. nov.

- Metafemur thin, normal shape, never with ventral spines..................................................... 22

22. Pattern of 3 rd tergum consisting of oblique maculae (Figs 9G)................................................. 23

- Pattern of 3 rd tergum different, triangular (Figs 28B, E, 49B, E), quadrate or rectangular (Figs 63B, E, 65B, E).......... 26 [Note: A. currani can be keyed out from both statements if couplet 22 is not properly evaluated; in A. currani the macular pattern is triangular, referred to as the inner margin of the maculae forming an acute angle (45°) with the basal margin of 3 rd tergum as can be seen in the Figs 28B, E].

23. Costal cell bare on basal 3/4 or more.................................................................... 24

- Costal cell entirely microtrichose........................................................................ 25

24. Protarsus black (Figs 24A–F); male genitalia: surstylus in lateral view (Fig. 25A) with dorsal and ventral margins approximately of the same width in the whole length; hypandrium in ventral view (Fig. 25C) narrowed laterally towards the apex; aedeagal lobe in ventral view (Fig. 25C) with acute apex [Costa Rica, Guatemala, El Salvador, Mexico and Panamá]................................................................................ Argentinomyia catabomba (Williston, 1891)

- Protarsus yellow..................................................................... Argentinomyia CR-14

25. Mesonotum punctate markings, shining bronze to aeneous, with brownish vittae on anterior half (Fig. 40C, E); female frontal triangle with two rounded maculae (Fig. 40D); 3 rd to 4 th terga with a pair of oblique yellow maculae (Figs 40B, E); male genitalia: surstylus in lateral view (Fig. 45A) with dorsal and ventral margins approximately of the same width in the whole length; aedeagal lobe in ventral view (Fig. 41C) with apex acute [ Argentina, Brazil and Ecuador] Argentinomyia lanei (Fluke, 1936)

- Mesonotum without punctuate markings (Figs 18C, E); frontal triangle with transversal black macula (Fig. 18D); the 3 rd tergum with a pair of elongate, slightly oblique yellow maculae, reaching the lateral margin and slightly touching each other towards the middle (Figs 18A–G); male genitalia: surstylus in lateral view (Fig. 19A) with dorsal margin slightly concave and ventral margin slightly convex; aedeagal lobe in ventral view (Fig. 19C) circular, apex rounded [Brazil and Venezuela]................................................................................. Argentinomyia berthae (Lima, 1946)

26. Metafemur yellow with a black ring or smudge on apical margin (Figs 7E, 28 B, C, 49B, C, F, 63B, C, 65C, F); female frontal triangle with two rounded brown pollinose maculae (Fig. 28D, 49D); 3 rd to 4 th terga with triangular maculae, the inner margin of the maculae forms an acute angle (45°) with the basal margin of the tergum (Figs 28B, E, 49B, E)................. 27

- Metafemur yellow without a black ring or smudge on apical margin (Figs 14C, F, 77C, F); female frontal triangle with a different pollinose pattern; 3 rd to 4 th terga with quadrate or rectangular maculae, the inner margin of the maculae forms a right angle (90°) with the basal margin of the tergum (Figs 63B, E, 65B, E).......................................... 28

27. Metatibia mostly yellow (Figs 49C, F); male genitalia: surstylus in lateral view (Fig. 50A) with dorsal margin slightly concave and ventral margin slightly convex, shorter than broad; hypandrium in ventral view (Fig. 50C) expanded laterally towards the apex; aedeagal lobe in ventral view (Fig. 50C) with apex acute [ Argentina and Brazil].................................................................................................... Argentinomyia maculata (Walker, 1852)

- Metatibia yellow on basal 1/4 (Figs 9I, 28C, F); male genitalia: surstylus in lateral view (Fig. 29A) with dorsal and ventral margins approximately of the same width in the whole length; hypandrium in ventral view (Fig. 29C) expanded laterally towards the apex; aedeagal lobe in ventral view (Fig. 29C) circular, apex rounded [Brazil and Perú].......................................................................................... Argentinomyia currani (Fluke, 1937)

28. Maculae on 3 rd tergum longer than wide, extending from the base to apical 3/4 or more (Figs 28B, E, 49B, E)........... 29

- Maculae on 3 rd tergum as long as wide, extending only from the base to apical 1/2 or less (Figs 63B, E, 65B, E)......... 30

29. Face more perpendicular and less produced ventrally, the sides thickly coated with cinereous yellow pollen (Figs 86A, D); metafemur reddish or yellowish on basal half, metatibia yellow on basal and apical 1/4 (Figs 86A C, F); maculae on female abdomen rectangular and apically rounded (Figs 86B–C, E–F); male genitalia: Aedeagal lobe in ventral view (Fig. 87C) with apex rounded [ Argentina, Brazil, Colombia, Ecuador and Venezuela]............... Argentinomyia tropica (Curran, 1937)

- Face slightly produced ventral, more prominent, facial pollen smooth and yellowish (Figs 47A, D); metafemur black, only very narrowly yellow basally (Figs 47C, F); maculae on female abdomen triangular (Figs 4B–C, E–F, 48D–H); male genitalia: aedeagal lobe in ventral view (Fig. 48C) with apex acute [Colombia, Ecuador and Venezuela].............................................................................................. Argentinomyia luculenta (Fluke, 1945) [Note: Some morphotypes of A. tropica and A. luculenta may key through either option. X. Mengual (personal communication) suggests both species could form a species complex, with two additional morphospecies not exanimated that could be new to science, however, a deep examination of male genitalia is needed to confirm them]

30. Metatibia mostly brownish apically (Figs 65C, F, 77C, F).................................................... 31

- Metatibia yellow.................................................................................... 32

31. Female frontal triangle with a medial white pollinose vitta (Figs 65D); metafemur obscured on apical 1/3 or little more; 3 rd and 4 th terga with maculae extending to the apical 1/2; 5 th tergum without a pair of small lateral rounded maculae; male genitalia: surstylus in lateral view (Fig. 64A) narrowed laterally towards the apex [Cuba, Dominican Republic and Jamaica].............................................................................. Argentinomyia praeusta (Loew, 1866)

- Frontal triangle with transversal golden-brownish pollinose band touching slightly the sides of the eyes (Figs 77D); metafemur yellow basally and slightly obscured on apical 1/5 dorsally; 3 rd and 4 th terga with maculae extending to the apical 2/3; 5 th tergum with a pair of small lateral rounded maculae (Figs 77A–F); male genitalia: surstylus in lateral view (Fig. 78A) very elongated and widened dorsally, with a small extension at the ventral margin [Dominican Republic]..................................................................................... Argentinomyia taina Thompson & Montoya sp. nov.

32. Face whitish pollinose and pilose (Figs 63A, D); female frontal triangle with a complete transverse black fascia (Figs 63D, 64D); metafemur yellow except the apical 1/5 narrowly brown (Figs 63C, F); male genitalia: surstylus in lateral view (Fig. 64A) with dorsal margin slightly concave and ventral margin slightly convex [ Argentina, Brazil and Venezuela]...................................................................................... Argentinomyia pollinosa (Hull, 1942)

- Face extensively covered by golden pollinose and pilose (Figs 14A, D); female frontal triangle with a transversal goldenbrownish pollinose band (Figs 14D, E); metafemur obscured on basal 2/6 and apical 1/6 or little more (Figs 14C, F); male genitalia: surstylus in lateral view (Fig. 15A) with dorsal and ventral margins approximately of the same width in the whole length [Dominican Republic]............................... Argentinomyia aurifacies Thompson & Montoya sp. nov.

33. 2 nd tergum entirely black (Figs 74B, E, 79B, E, 84B, E)...................................................... 34

- 2 nd tergum with some lateral yellow maculae (Figs 10B, E, 61B, E, 90B, E, 91B, E, 88B, E)......................... 37

34. Abdominal maculae metallic blue; wing extensible hyaline; legs dark brown, only slightly white-yellowish on apical 1/6 (Figs 39A–C) (male unknown) [Jamaica].................................. Argentinomyia jamaicensis Montoya sp. nov. [Note: Female frontal triangle of A. jamaicensis Montoya sp. nov. has a medial white pollinose vitta (see Fig. 39A), also found in female of A. praeusta]

- Abdominal maculae yellow to orange; wing brownish apically; legs coloration variable............................. 35

35. Wing slightly darkened in the anterior margin from the costal cell to the stigma, cells r1 and r4+5, with some small hyaline areas (Figs 84B, C, E, F); metafemur and protibia black (Figs 84A, C, D, F); male genitalia: surstylus in lateral view (Fig. 85A) with dorsal margin slightly concave and ventral margin slightly convex; aedeagal lobe in ventral view (Fig. 85C) circular, apex rounded [Bolivia, Colombia, Ecuador and Perú]........................ Argentinomyia tropandeana Montoya sp. nov.

- Wing hyaline; other characters variable.................................................................. 36

36. Antennae brownish, orange ventrally (Fig. 79A); frontal triangle golden pollinose (Fig. 79A); metanotum golden pile; terga 3 rd and 4 th with a pair of basolateral rectangular maculae extending 1/3 of tergum length (Fig. 79B–C); male genitalia: surstylus in lateral view (Fig. 80A) shorter than the epandrium, with dorsal margin slightly concave and ventral margin slightly convex; dorsal area of the apex of hypandrium (superior lobes) in lateral view, no extending dorsally backward, without a small sclerotized inner spur; the base of the aedeagus no globose [Colombia]........... Argentinomyia teresae Montoya sp. nov.

- Antennae black (Fig. 74A); frontal triangle dark pollinose (Fig. 74A); metanotum with mixed black and gold pile; terga 3 rd and 4 th with a pair of orange macula extending 1/6 of tergum length and restricted to basolateral margins (Figs 74A–C); male genitalia: surstylus in lateral view (Fig. 75A) larger than the epandrium, with dorsal margin slightly concave, the apico-dorsal edge rounded; dorsal area of the apex of hypandrium (superior lobes) in lateral view, extending dorsally backward, with a small sclerotized inner spur; the base of the aedeagus globose [Colombia]........... Argentinomyia serendipia Montoya sp. nov.

37. Antenna entirely black (Figs 37, 57, 59, 67)............................................................... 38

- Antenna partially pale ventrally, at least orange-yellow ventrally on basoflagellomere (Figs 42, 51, 53)................ 42

38. 2 nd tergum almost entirely yellow, but with a thin median black stripe and narrow posterior black margin; the 3 rd and 4 th terga yellow with a median black stripe and narrow posterior black margin; the 5 th tergum yellow with only a small posteromedian black triangle (Figs 10A–F, 6D), female abdominal maculae comparatively wider than in the male; male genitalia: surstylus in lateral view (Fig. 11A) with dorsal and ventral margins approximately of the same width in the whole length, elongated, three to four times longer than broad; hypandrium in ventral view (Fig. 11C) narrowed laterally towards the apex; aedeagal lobe in ventral view (Fig. 11C) circular, apex rounded (Ecuador: Galápagos Islands)......... Argentinomyia agonis (Walker, 1849)

- 3 rd and 4 th terga with basal rectangular macula extending at least 2/3 of segment length............................. 39

39. Metafemur entirely black, pro- and mesotibiae black, only yellow on basal 1/4, metatibia yellow on basal 1/2, tarsi black (Figs 61A, C); 2 nd tergum with a pair of basolateral elongate yellow maculae reaching the apical 3/4 of the segment length; 3 rd tergum with a pair of basal elongated maculae reaching apical 2/3, but not reaching lateral margin (Figs 61B); male genitalia: surstylus in lateral view (Fig. 62A) with dorsal margin slightly concave and ventral margin slightly convex; hypandrium in ventral view (Fig. 62C) narrowed laterally towards the apex; aedeagal lobe in ventral view (Fig. 62C) circular, apex rounded (female unknown) [Brazil]....................................... Argentinomyia plaumanni Thompson & Montoya sp. nov.

- Metafemur mainly yellow; abdominal maculae pattern different; other characters different [Central America]........... 40

40. Male with broad shiny facial vitta; pleuron, scutum and scutellum black pilose; wing with indistinct brown fascia on cross-vein r-m [Costa Rica]..................................................................... Argentinomyia CR-12

- Male facial vitta narrow, indistinct dorsally............................................................... 41

41. Abdominal maculae small, isolated from lateral margins; male genitalia normal size [Costa Rica]..... Argentinomyia CR-13

- Abdominal maculae large, extending over lateral margin; metafemur orange; male genitalia large [Costa Rica]............................................................................................... Argentinomyia CR-2

42. Metafemur yellow on apex and basal 1/5; pro- and mesofemora broadly yellow on apical 1/3 to 1/4, respectively; protibia black; abdominal maculae linear reaching to apical 4/5 of segment length (Figs 9F, 42A–F); male genitalia: surstylus in lateral view (Fig. 43A) square-like; hypandrium in ventral view (Fig. 43C) narrowed laterally towards the apex; aedeagal lobe in ventral view (Fig. 43C) oval, apex rounded [Brazil and Bolivia].......................... Argentinomyia lineata (Fluke, 1937)

- Metafemur black, at most only the apex or narrow base yellow; pro- and mesofemora broadly brown on basal 2/3, protibia yellow; other characters variable........................................................................ 43

43. Abdomen with yellowish red triangular maculae on the basal corners of the 2 nd tergum, reaching over the sides and 1/2 of the segment’s length (Figs 9C, 53B, E); pro and mesofemora black, only narrowly yellow towards the apex, metatibia slightly yellow basally (Figs 53B, E); male genitalia: surstylus in lateral view (Fig. 54A) with dorsal and ventral margins similar (square-like); aedeagal lobe in ventral view (Fig. 54C) circular, apex rounded [ Argentina, Brazil and Colombia]................................................................................. Argentinomyia nigrans (Fluke, 1945)

- Abdomen with large yellow triangular maculae, two pairs of maculae on 3 rd and 4 th terga of male, three pairs of maculae on 2 nd to 4 th terga of female; metafemora black, only yellow basally and apically (Figs 51B, C, E, F, 52D); male genitalia: surstylus in lateral view (Fig. 52A) triangular-like; aedeagal lobe in ventral view (Fig. 52C) with apex acute [ Argentina, Brazil, Colombia and Paraguay]........................................................ Argentinomyia neotropica (Curran, 1937)

44. Antenna entirely black (Figs 37, 57, 59, 67)............................................................... 45

- Antenna partially pale ventrally, at least orange-yellow ventrally on the basoflagellomere........................... 48

45. Abdomen black with grey metallic maculae (Figs 37B, E, 59B, E); pro- and mesotibiae dark brown, only slightly yellowishorange either basally or apically (Figs 37C, F, 59C, F)....................................................... 46

- Abdominal maculae yellow to orange (Figs 57B, E, 67B, E); pro- and mesotibiae yellow with a dark median ring (Figs 57C, F, 67C, F)............................................................................................ 47

46. Tubercle not deeply concave dorsally (Figs 37 A-C); scutum yellow pilose; halter black; male genitalia: surstylus in lateral view (Fig. 38A) shorter than the epandrium; hypandrium in ventral view (Fig. 38C) acuted laterally towards the apex; apex of hypandrium (superior lobes) no feline claw shape, with a lateral rounded extension (Fig. 38C) (female unknown) [Perú].......................................................... Argentinomyia jalcaensis Thompson & Montoya sp. nov.

- Tubercle well-rounded, deeply concave dorsally (Figs 59A–F, 60D–E); scutum mainly black pilose; halter white; male genitalia: surstylus in lateral view (Fig. 60A) comparatively longer than the epandrium; hypandrium in ventral view (Fig 60B) rounded laterally towards the apex; apex of hypandrium (superior lobes) feline claw shape [Colombia and Ecuador]....................................................................................... Argentinomyia opaca (Fluke, 1945)

47. Abdomen with a pair of rectangular yellow vitta on 2 nd to 4 th terga, maculae on 2 nd tergum rectangular and entirely isolated from base and apex, maculae on 3 rd reach base and extend to apical 1/5, maculae on 4 th similar and extending to apical 1/3 (Figs 67A–F); male genitalia: surstylus in lateral view (Fig. 68A) with dorsal and ventral margins approximately of the same width in the whole length, elongated, three to four times longer than broad; aedeagal lobe in ventral view (Fig. 68C) circular, apex rounded [Colombia and Ecuador].............................................. Argentinomyia rex (Fluke, 1945)

- Abdomen with a pair of thin maculae (diamond shape) covered with gray pollen on 3 rd to 4 th terga of male, the same type of macula on 2 nd to 5 th terga of female, maculae on all segments isolated from base and apex (Figs 57, 58D–E); male genitalia: surstylus in lateral view (Fig. 58A) bent back as a Z in shape, no more than two times longer than wide; aedeagal lobe in ventral view (Fig. 58C) with apex acute [Colombia]................................... Argentinomyia occidentalis sp. nov.

48. Pro- and mesofemora and tibia yellow, sometimes only dark brown on dorsal surface; face above tubercle carinate (Figs 4H, 22A, D); female frontal triangle without a complete transverse black fascia; maculae starting at the base, covering 5/6 of the length of the 2 nd tergum (Figs 22A–F); male genitalia: surstylus in lateral view (Fig. 23A) with dorsal and ventral margins slightly concave; aedeagal lobe in ventral view (Fig. 23C) with apex acute. Elongate species, more than 10 mm [Colombia, Ecuador and Venezuela].................................................. Argentinomyia browni (Fluke, 1945)

- Pro- and mesofemora usually black or brown, never completely yellow, at least basal 1/4 dark, other charters variable.... 49

49. Abdominal maculae almost as wide as long, maculae on 3 rd tergum of male quadrate and on female triangular; facial pile mostly black on male; pro- and mesotibiae orange with a dark median ring (Figs 12A–F, 13D–E); male genitalia: surstylus in lateral view (Fig. 13A) very elongated and widened ventrally, with a median sized extension in the dorsal margin; aedeagal lobe in ventral view (Fig. 13C) hearth shape, with the apical margin concave [Colombia, Ecuador, Perú]............................................................................................ Argentinomyia altissima (Fluke, 1945)

- Abdominal maculae slenderer, elongated, about two and 1/2 times as long as wide on 3 rd tergum; female abdomen usually black and covered by grey pollinosity, at most with small reddish maculae (Figs 20B, E); face with even brown-yellowish pollen except near antennae (Figs 20A, D); pro- and mesotibiae without a dark median ring (Figs 20A–F); male genitalia: surstylus in lateral view (Fig. 21A) with dorsal margin slightly concave and ventral margin slightly convex; aedeagal lobe in ventral view (Fig. 21C) with apex acute [Colombia and Ecuador]........................ Argentinomyia bolivariensis (Fluke, 1945)