Description of six new large species of Argentinomyia Lynch-Arribálzaga, 1891 and redescription of Talahua fervida (Fluke, 1945) (Diptera, Syrphidae, Syrphinae)

Abstract The morphological similarities between five new large Argentinomyia species and Talahua fervida Fluke are characterized and presented. Six new species of Argentinomyia (10–12 mm long) are described: Argentinomyia andina Montoya & Wolff, sp. nov. (Colombia), Argentinomyia choachi Montoya, sp. nov. (Colombia), Argentinomyia quimbaya Montoya & Wolff, sp. nov. (Colombia), Argentinomyia huitepecensis Montoya, sp. nov. (México), Argentinomyia puntarena Montoya, sp. nov. (Costa Rica), and Argentinomyia talamanca Thompson, sp. nov. (Costa Rica). The genus Talahua Fluke is re-diagnosed and, Talahua fervida redescribed. A taxonomic key and a comparison of diagnostic characters are presented. Photographs of head, abdominal and wing maculae patterns, as well as illustrations of male genitalia are provided for species identification.


Introduction
Flower flies or hoverflies (Syrphidae) are one of the most diverse families of Diptera with more than 6100 described species worldwide, and ca. 1560 species distributed in the Neotropical region (Thompson et al. 2010;Pape and Evenhuis 2018). Currently, the family is subdivided into four subfamilies: Syrphinae, Pipizinae, Eristalinae, and Microdontinae (Mengual 2015). Syrphinae comprises more than 30% of worldwide diversity of the family and contains mostly species with larvae that feed on soft-body arthropods (Rojo et al. 2003). Within Syrphinae, the tribe Bacchini comprises 332 species worldwide (13 genera) and more than 83 Neotropical species classified into seven genera: Melanostoma Schiner, 1860 is present in all biogeographic regions (Haarto and Ståhls 2014); in the Neotropics, only Melanostoma bellum Giglio-Tos, 1892 is found in Chiapas, México, but may also occur in the adjacent highlands of Guatemala (Thompson et al. 2010). Platycheirus Lepeletier &Serville, 1828 andXanthandrus Verrall, 1901 are widely distributed in the Neotropics and other biogeographic regions (Vockeroth 1990;Borges and Pamplona 2003;Mengual et al. 2008). Genera Argentinomyia Lynch-Arribálzaga, 1891, Leucopodella Hull, 1949, Tuberculanostoma Fluke, 1943, and Talahua Fluke, 1945 are Neotropical endemics and reach the highest diversity in the highlands of the Tropical Andes (Fluke 1943(Fluke , 1945(Fluke , 1957Thompson 1981Thompson , 1999, with some species of Argentinomyia and Leucopodella extending to Central America. Argentinomyia contains 27 valid species distributed from the cloud forests in Northern Central America to low and middle elevations in the Caribbean and Galápagos Islands. The genus is also found in cold Andean forests and Páramo ecosystems in the Tropical Andes, and in lowlands in southeastern of South America. Even though extensive sampling has been done, the genus is apparently absent in the Chilean subregion and, has not been registered in Surinam (Thompson 1999;Thompson et al. 2010;Reemer 2010). Adults of Argentinomyia are common flower visitors in pristine ecosystems, whilst immature stages are unknown.
Argentinomyia is distinguished from other genera of Bacchini by the combination of: 1) long antenna, with scape much longer than broad; 2) basoflagellomere oval or slightly elongate; 3) face straight in profile, not produced anteriorly, generally with pollinosity broadly punctuate, tubercle low, usually with transverse grooves dorsally or pollinosity broadly punctuate; 4) metacoxa without posteromedial pile on apical angle; 5) abdomen dark colored, often with variously shaped light-colored yellow, orange to silvery-grey pollinose paired maculae; triangular to quadrate or oval markings on 2 nd to 4 th abdominal tergite, sometimes including a small macula on 5 th tergite, and 6) male genitalia normal size, superior lobes triangular to rectangular, irregular in shape and cercus short (Fluke 1945(Fluke , 1957Thompson 1999;Huo 2014;Thompson and Skevington 2014).
Talahua is a small Neotropical genus that inhabits the highlands of Colombia and Ecuador (Fluke 1945;Montoya et al. 2012;Montoya 2016;Marín-Armijos et al. 2017). The genus was originally established by Fluke (1945) as subgenus of Melanostoma, including the only species Melanostoma (Talahua) fervida Fluke, 1945. In a subsequent study, Fluke (1957) gave Talahua full generic status based on the study of male genitalia. Later, Thompson et al. (1976) also considered Talahua a valid genus. In 1999, Thompson proposed to transfer the aberrant species, Melanostoma palliatum Fluke, 1945 to Talahua, despite the species being previously considered part of Xanthandrus (Thompson et al. 1976). In the revision of the Neotropical Xanthandrus, Borges and Pamplona (2003) considered M. palliatum as part of Xanthandrus, and consequently, Talahua was again recognized as monotypic (Borges and Pamplona 2003;Marín-Armijos et al. 2017; Thompson and Skevington 2014).
Talahua can be distinguished from other genera of Bacchini largely by the following combination of characters: 1) antennae relatively short, scape broader than long, nearly equal to pedicel; 2) basoflagellomere large, slightly oval and apically rounded; 3) face slightly receding to perpendicular with a well-rounded tubercle, never with transverse grooves dorsally along tubercle or broadly punctuate; 4) metacoxa with a tuft of pile at posteromedial apical angle; 5) abdomen elongated or with parallel sides, with four to five pairs of large rounded to triangular markings on the terga, always with small macula on 5 th tergum; and 6) male genitalia greatly enlarged, with superior lobes, and cerci elongated, surstyli three to four times longer than broad (Fluke 1945(Fluke , 1957Thompson 1999;Thompson and Skevington 2014).
Extensive sampling in the cloud forest, high-Andean and Páramo ecosystems in Mesoamerica (México and Costa Rica) and Tropical Andes (Colombia and Ecuador) in the last twenty-five years resulted in the discovery of several new Argentinomyia species including six species, large in body size, that are similar in appearance to Talahua fervida. Therefore, we take the opportunity to describe the new species and provide a full redescription for T. fervida, as well as a taxonomic key, photographs, illustrations, and a comparison of morphological diagnostic characters, including distributional maps to all species.

Material and methods
Syrphidae-specific characters used in the key, descriptions, and drawings largely follows the terminology established by Thompson (1999), Thompson et al. (2010), and Cumming and Wood (2017). Figures of some characters employed in the key correspond to those treated in the chapter of Syrphidae in the Manual of Central America Diptera (Thompson et al. 2010) and are indicated by the abbreviation "MCAD". The specimens were determined to genus level using the keys of Thompson et al. (2010), Huo (2014) and Thompson and Skevington (2014). Our new species were compared with type specimens of twenty-seven Argentinomyia species and one of Talahua deposited in the AMNH, BMNH, USNM, and WIRC collections (Suppl. material 1), including the study of the original descriptions (Fluke 1945). A complete revision of the genus is in preparation and will be published soon. Recognition of the new species was facilitated by examination and comparison of the reference material of Argentinomyia identified by F. C. Thompson  The type series of the new species is comprised of dry pinned material deposited in the CEUA, USNM, INBio, and ECO-TAP-E.
To illustrate the morphological variation of the herein described species, habitus photographs were created from a series of images taken at different focal depths with a digital camera Olympus OM-D (Olympus Raw Image file in .ORF) using the facilities of the Diptera Collection, Department of Entomology (https://naturalhistory. si.edu/research/entomology/collections-overview/diptera-collection) at the USNM. Additional photos were taken using a Moticam 3.0 megapixel DFC500 digital camera attached to an Olympus SZX7 stereomicroscope. Final images were combined using the HeliconFocus Pro (version 6.7.1) stacking software. The scale bar was added in Photoshop according to the camera focal aperture used when the photo was taken. Editing was conducted in Adobe Photoshop CC, and the final image plates were prepared in Illustrator CC.
Body length was measured from frons to the posterior end of the abdomen; wing length was measured from wing insertion to the apex of the wing. Measurements were made using a Zeiss Stemi 2000-C stereomicroscope (magnification 6.5-115×) equipped with a stereoscope grid. Measurements of antennal segments are approximations based on the mid-line of the inner surface and are presented in the ratio format scape:pedicel:flagellomere.
For the study of the male genitalia, the structure was dissected. The genitalia were cleared in a KOH solution (approximately 10%) boiling at 37 °C for 10 to 15 minutes. Schema of internal structures were illustrated from digital images taken through the stereomicroscopes. Additional, sketches were produced with a camera Lucida attached to the stereomicroscope. Final drawings were prepared by tracing and vectorizing in Adobe Illustrator CC, and pile was omitted.
The new species are described from males and females collected together in at least one locality, and sexual dimorphic variation reported. Only Argentinomyia choachi Montoya sp. nov. is described from a single female because it markedly differs in the morphological characters from the other species.
With the aim of spanning the entire known distribution of included species, original label information was compiled in a Darwin Core standard-compliant data. Distributional maps were generated using the software QGIS desktop 2.2.0 and an excel .csv file (comma delimited) to plot presence. A digital file with an elevation model (SRTM30 CGIAR-SRTM with 30 seconds resolution) was used in addition to a shapefile with the biogeographic provinces proposed by Morrone (2014) and digitalized by Löwenberg-Neto (2015) for the Neotropics.

Description of new species
The new Argentinomyia species described here are characterized by the scutellum with a deep groove next to the rim (emarginate), face with a well-rounded tubercle, never with transversal grooves dorsally along tubercle or broadly punctuate, metacoxa with a tuft of pile at posteromedial apical angle, wing generally with a brownish macula extensively covering the apex of cells r and m or hyaline, and abdomen with large markings on the terga. The new species are superficially similar to Talahua fervida, differing in the male genitalia.
Identification key to the large (10-12 mm long) species of Argentinomyia The new key was modified based on characters provided by Thompson (1999), Thompson et al. (2010), Huo (2014), Thompson and Skevington (2014) and Ramage et al. (2018). Antennae shorter, scape broader than long, scape nearly equal to pedicel, basoflagellomere large, slightly oval and apically rounded ( Differential diagnosis. Face yellow pollinose and pilose. Metafemur extensively brown, only slightly orange on apical 1/6. Tibiae yellow with a dark ring near the middle, more prominent on the metalegs. Third and fourth tergum with a pair of broad subquadrate maculae, reaching the lateral margin in their full width, fifth tergum with a pair of small maculae in the basal corners. Argentinomyia puntarena sp. nov. is similar to A. andina sp. nov., but differs in having the face white pollinose and pilose; metafemur orange on basal 1/5 and apical 3/5, metatibia extensively brown, only orange brownish on basal 2/3; fifth tergum without maculae. Type locality. Colombia, department of Antioquia, Sonsón municipality, Vereda Norí municipal rural settlement, Norí Mountain hill, forest, 05°48.580'N, 75°16.142'E, alt. 2896 m a.s.l. Description. Male. Head (Fig. 1A, C): Black metallic, covered with yellow pollinosity, oral tips, ocellar triangle, and a large triangular macula on the frons, yellow pilose, pile on front black, on gena and face golden yellow, on the occiput yellow except the dorsal pile black, frontal triangle coppery metallic. Antennae brown, orange-red ventrally, rounded, as long as wide, the lower basal corner of basoflagellomere, ratio 1.0:1.2:2.3, arista orange, dark brown toward the tip. Thorax (Fig. 1C). Black, the scutum shining, with iridescent to coppery yellow reflections, with two median brownish pollinose vittae on anterior half, pile mostly yellow, with long black pile before the scutellum. Wing (Fig. 1C). Slightly smoky, the stigma brown yellowish, marginal maculae slightly brownish at apex of cells r and m; membrane microtrichose, except for extensive bare areas on basal half (cells c, sc, r1, dm and bm); tegula and basicosta black pilose, alula extensively bare medially, calypter whitish yellow, border whitish tawny, fringe yellow tawny, plumula yellow, halter white, knob white. Legs (Fig. 1C). Yellow to brown, pro and mesofemora brown, only slightly yellow on apical 1/3, respectively, metafemora brown, only slightly orange on apical 1/6, tibiae yellow with a dark ring near the middle, more prominent on the metalegs, tarsi brown, yellow pilose below, black pilose above. Abdomen (Fig. 1B). Elongate, black, with five pairs of lateral orange maculae reaching the apical 5/6 of the tergum, first tergum shining black, second to fourth tergum with a pair of broad subquadrate maculae, reaching the lateral margin in their full width; fifth tergum with a pair of small maculae in the basal corners. Pile orange on the sides basally, black down the middle and on the apical terga, as well as in the maculae; male genitalia as Fig. 2.
Female. (Fig. 1D-F). Similar to male except for normal sexual dimorphism. Abdominal maculae triangular and comparatively shorter than in the male, apically rounded, second to fifth tergum with maculae only reaching the apical 3/4, but not reaching the lateral margin in their full width. Frons shining above with a white pollinose transversal macula below. The female of Argentinomyia andina sp. nov. is similar in appearance to Talahua fervida, but T. fervida has a pair of small basolateral maculae on the sixth tergum and maculae on second to third tergum are longer than in A. andina sp. nov.
Length (N = 2). Body 11.2-11.5 mm; wing 10.8-11.1 mm. Etymology. The specific epithet andina (nominative, adjective feminine) is derived from the Andes South American mountain chain system where the type specimens were collected.
Distribution. Argentinomyia andina sp. nov. (N = 8) is distributed on the west slope of the Central Cordillera in Northern Colombian Andes (Antioquia) at elevations between 1800-2700 m. a.s.l., in the provinces of Cauca (Fig. 15). Comments. Argentinomyia andina sp. nov. inhabits pristine Andean forest and Páramo ecosystems in Colombia, being particularly abundant in forest. Differential diagnosis. Abdomen with a pair of large quadrangular maculae on the third and fourth tergum, sometimes slightly touching toward the middle. Legs black, metafemur only slightly yellow in the extreme apex. Coxae black. Metacoxa yellowish pilose. Argentinomyia choachi sp. nov. is similar in appearance to the female of Argentinomyia andina sp. nov. but in A. andina sp. nov. the third and fourth tergum have a pair of short rounded basal maculae; metafemur is extensively brown, only slightly orange on apical 1/6; all coxae yellow.
Description. Female. Head (Fig. 3A, C). Black, covered with white pollinosity, oral tips, ocellar triangle, and a large triangular macula on the front, white pilose, pile on front black, on gena and face white, on ocellar triangle black, on the occiput white except for the dorsal pile, which are black. Antennae brown, orange-red ventrally, oval, longer than wide pedicel and the lower basal corner of basoflagellomere, ratio 1.0:1.3:3.1, arista orange, brown toward the tip. Thorax (Fig. 3C). Black cyaneous, the scutum shining, with iridescent to coppery reflections in the notopleura, with two median yellowish pollinose vittae on anterior half. Wing (Fig. 3C). Smoky apically, the stigma yellow-brown, membrane microtrichose, except for extensive bare areas on basal half (cells c, sc, r1, dm and bm); tegula black pilose, basicosta yellow pilose, alula bare, calypter whitish tawny, border whitish brown, fringe tawny, plumula yellow, halter white, knob white. Legs (Fig. 3C, D). Black, pro and mesofemora yellow on the apical two-thirds; metafemora only slightly yellow in the extreme apex, pro and mesotibia with lateral maculae on posterior medial edge, metatibia extensively brown, only yellow on basal 2/7 and apical 1/7; protarsi black, meso-and metabasitarsus yellow, the pile yellow, black on the metatibia and above on the tarsi; coxa black, metacoxa yellowish pilose. Abdomen (Fig. 3B). Elongate, black, with two pairs of lateral yellow pale maculae, first tergum shining black, second with broad lateral yellow maculae and only the apex black, third with rounded lateral maculae. Pile yellow-white on the maculae and only a few black down the middle and on the apical terga. Sterna black, black pilose.
Male. Unknown. Length (N = 1). Body, 11.5-12.3 mm, wing, 10.2-10.4 mm. Etymology. The specific epithet "choachi" is a noun in apposition and refers to the name of the town where the type specimen was collected. Coachí is a Muiscas word derived from "Ch-igua-chía", which means the window where the moon peeked, received the poetic name of "Window of the moon" (according to Miguel Triana). The Muiscas were indigenous people who inhabit the "Altiplano Cundiboyacense" formed by high plains on the eastern Cordillera in Colombian Andes between the departments of Cundinamarca and Boyacá, where the species was collected.
Distribution. Argentinomyia choachi sp. nov. (N = 1) is present on the western slope of Oriental Cordillera in Colombia (Cundinamarca) at 2240 m. a.s.l., inhabiting cloud forest in the provinces of North Andean Páramo (Fig. 15) Description. Male. Head (Fig. 4A, C). Black, covered with white pollinosity, oral tips, ocellar triangle, and a large triangular macula on the front, brown pilose, pile on front black, on gena and face white pilose, on ocellar triangle black pilose, on the occiput white except the dorsal pile, which are black, frontal triangle golden metallic. Antennae brown, orange-red ventrally, oval, longer than wide pedicel and the lower basal corner of basoflagellomere, long, ratio 1.0:1.2:3.0, arista orange, dark brown toward the tip. Thorax (Fig. 4C). Black, the scutum opaque, shining, with iridescent to opaque reflections, with two median brownish pollinose vittae on anterior half. Wing (Fig. 4C). Slightly smoky, the stigma brown, membrane microtrichose, except for extensive bare areas on basal half (cells, c, sc, r1, dm and bm); tegula black pilose, basicosta yellow pilose, alula bare, calypter whitish, border whitish, fringe yellow, plumula yellow, halter yellow, knob white. Legs (Fig. 4C). Yellow, pro-and mesofemur yellow; metafemur orange on basal 1/5 and apical 3/5; pro-and mesotibia orange with a brown macula on posterior medial edge, metatibia extensively brown, only orange brownish on basal 2/3; metacoxa black pilose; pro, meso-and metabasitarsomere I-II yellow, the pile yellow, black on the metatibia and above on the tarsi. Abdomen (Fig.  4B). Elongate, black, first tergum shining black, second tergum with a pair of broad maculae, reaching apical 1/2, third tergum with a short rounded basomedial fascia. Pile orange on the sides basally, black down the middle and on the apical terga, as well as in the maculae. Male genitalia as Fig. 5.
Female. (Fig. 4D-F). Similar to male except for normal sexual dimorphism. Abdominal maculae on tergum third comparatively shorter than in the male and re- stricted to the center of the tergum, no reaching the lateral margin, maculae on fourth and fifth tergum absent.
Length (N = 5). Body 12.5-12.8 mm; wing 11.4-11.7 mm. Etymology. The specific epithet huitepecensis (noun in the genitive case) is derived from the Mixtec (native language spoken in México) word "Huitztli" which means: thorns, "Tépeltque" means: hill, combined with the Latin suffix -ensis, meaning from a place. The name is given in reference to the Huitepec Ecological Reserve where the species was collected. Distribution. Argentinomyia huitepecensis sp. nov. (N = 7) is the northernmost distributed species of the larger Argentinomyia, recorded on the western slope of the Chiapas-Guatemalan Highlands, and inhabiting cloud forest at an elevation between 1800 to 2400 m. a.s.l. The species is exclusively known from the province of Chiapas Highlands (Fig. 16).  ange on basal 1/5 and apical 3/5. Probasitarsomere, meso-and metabasitarsomere I-II yellow. Second tergum with a broad macula reaching apical 1/3. Third tergum with a broad macula, short in fourth. Sternite fourth to fifth black pilose. Argentinomyia puntarena sp. nov. is similar in appearance to Argentinomyia talamanca sp. nov., but in A. talamanca sp. nov. the antenna is brown; alula and costal cell are extensively microtrichose; femur is extensively brown; the second tergum has a pair of small maculae on basal 1/5 (see 'diagnostic features' under each species or key). Description. Male. Head (Fig. 6A, C). Black, covered with white pollinosity, ocellar triangle, and a large triangular macula on the front, brown pilose, pile on front black, on gena and face white pilose, on ocellar triangle black pilose, on the occiput white except for the dorsal pile, which are black, frontal triangle golden metallic. Antennae brown, orange-red ventrally, oval, longer than wide pedicel and the lower basal corner of basoflagellomere, ratio 1.0:1.1:2.9, arista orange, dark brown toward the tip. Thorax (Fig. 6C). Black, scutum shining, with iridescent to opaque reflections, with two median brownish pollinose vittae on anterior half. Wing (Fig. 6C). Slightly smoky, the stigma brownish, membrane microtrichose, except for extensive bare areas on basal half (cells, sc, r1, dm and bm); costal cell hyaline, bare on basal 1/2; marginal maculae restricted to surrounding areas of veins R1, R4+5 and M1 apically; tegula black pilose, basicosta yellow pilose, alula bare medially, calypter whitish, border whitish, fringe yellow, plumula yellow, halter yellow, knob white. Legs (Fig. 6C). Yellow, pro-and mesofemur yellow; metafemur brown, except orange on basal 1/5 and apical 1/5; pro and mesotibia orange, metatibia extensively brown, only orange brownish on basal 2/3; probasitarsomere, meso-and metabasitarsomere I-II yellow, the pile yellow, black on the metatibia and above on the tarsi. Abdomen (Fig. 6B). Elongate, black, the first tergum shining black, orange laterally, the second tergum with a broad macula reaching apical 1/3 laterally; third tergum with a broad triangular macula, which is short in the fourth tergum; fourth and fifth sterna black pilose. Pile orange on the sides basally, as well as in the maculae, black down the middle and on the terga apex. Male genitalia as Fig. 7.
Female. (Fig. 6D-F). Similar to male except for normal sexual dimorphism. Frons with pollinose transversal maculae below. Abdominal maculae are comparatively shorter than in the male and indistinguishable in the fourth tergum.
Length (N = 4). Body 12.4-12.6 mm; wing 11.3-11.5 mm. Etymology. The specific epithet puntarena is a noun in apposition and refers to the province where the type series was collected.
Distribution Comments. Argentinomyia puntarena sp. nov. and Argentinomyia talamanca sp. nov. can be confused or mistakenly identified as Xanthandrus mexicanus Curran, 1930 due to the superficial similarity of these species. However, X. mexicanus can be distinguished by the presence of the antennal cavity broadly confluent (synapomorphy for Xanthandrus); the central portion of epistoma moderately prominent; the face entirely white pollinose and pilose; the pleura black with white pollinosity; metaepisternum with some fine subappressed long pile (distinctive of Xanthandrus); the abdomen oval, wide and flat, opaque, with yellow-orange triangular maculae on second to the fourth tergum, and the male genitalia with surstylus elongated, apically widened (Borges and Pamplona 2003:162, figs 33-37).

Argentinomyia quimbaya Montoya & Wolff, sp. nov.
http://zoobank.org/242B50C6-57FD-4B8E-AA43-65337E1A3D7D Figures 8, 9, 15 Differential diagnosis. Legs extensively yellow. Tegula yellow pilose and the halter entirely yellow. Abdomen with four pairs of lateral broad yellow maculae. Argentinomyia quimbaya sp. nov. is similar in appearance to Argentinomyia andina sp. nov., but in A. andina sp. nov. the legs are extensively brown, metafemur only slightly orange on apical 1/6. Tibiae yellow with a dark ring near the middle. Fifth tergum with a pair of small maculae in the basal corners (see 'diagnostic features' under each species or key).
Description. Male. Head (Fig. 8A, C). Black, covered with yellowish gray pollinosity, shining black on the prominent round tubercle, oral tips, ocellar triangle, and a large triangular macula on the front; pile on front black, on gena and face yellow, on ocellar triangle black, on the occiput yellow except the dorsal pile, which are black. Antennae brown, orange-red ventrally, oval, longer than wide pedicel and the lower basal corner of basoflagellomere, long, ratio 1.0:1.2:3.1, arista orange, dark brown toward the tip. Thorax (Fig. 8C). Black, the scutum shining, covered with coppery pollen and short golden pile with many long black hairs that appear yellowish at the base; these hairs become longer posteriorly and longer on the scutellum, fringe of scutellum yellow; pleura yellow pollinose and pilose. Wing (Fig. 8C). Smoky; the stigma brown yellowish; membrane microtrichose, except for extensive bare areas on basal half (cells c, sc, r1, dm, and bm); tegula yellow pilose, basicosta yellow pilose, alula extensively bare, calypter and plumule yellow; halter entirely yellow. Legs (Fig. 8B). Yellow, protarsi 1 yellow, 2-4 brown, 5 yellow, mesotarsi 1-2 yellow, 3-4 black, 5 yellow, metatarsi yellow. Abdomen (Fig. 8B). Elongate, black, with four pairs of lateral yellow maculae; first tergum shining, laterally yellow, second tergum with the broad lateral yellow maculae reaching the segment apex, third tergum with wide rectangular lateral maculae, which are apically rounded and reach the apical 6/7 of the segment, fourth tergum with still wider but less elongate maculae, reaching only ½ of the segment length. Pile yellow on the sides basally, black down the middle and on the apical terga. Male genitalia as Fig. 9.
Female. (Fig. 8D-F). Similar to male except for normal sexual dimorphism. Abdominal maculae are comparatively wider than in the male. Front narrow above, not the much wider than the ocellar triangle, shining above with pollinose transversal maculae below; legs extensively yellow.
Length (N = 2). Body 11.8-12.3 mm; wing 11.5-11.9 mm. Etymology. The specific epithet quimbaya (noun in the genitive case) refers to the indigenous people who inhabit the Central Cordillera of the Colombian Andes in pre-Colombian times, between the departments of Caldas and Risaralda. The name also refers to the Flora and Fauna Sanctuary (SFF, acronym in Spanish) Otún Quimbaya, where part of the type series was collected. Differential diagnosis. Antenna brown, rounded, as long as wide; face opaque, white pollinose and pilose. Wing, alula and, costa cell extensively microtrichose, except for extensive bare areas on basal half (cells, sc, r1, dm, and bm); costal cell brownish, calypter and border whitish, fringe plumula and, halter yellow, knob white. Femora and tarsi extensively brown. Abdomen, second tergum with a pair of small narrow maculae reaching basal 1/5; third and fourth tergum with basomedial maculae, reaching 2/5 and 1/5, respectively; fifth sternite black pilose. Argentinomyia talamanca sp. nov. is similar in appearance to Argentinomyia puntarena sp. nov., but in A. puntarena sp. nov. the antenna is orange ventrally, oval, longer than broad; costal cell hyaline, bare basally; alula bare medially; pro-and mesofemur yellow; metafemur orange on basal 1/5 and apical 3/5; pro-, meso-and metabasitarsomere I-II yellow; second tergum with a broad maculae reaching the apical 1/3; third tergum with a broad macula, short in the fourth; sternite fourth to fifth black pilose (see 'diagnostic features' under each species or key).
Description. Male. Head (Fig. 10A, C). Black, covered with white pollinosity, oral tips, ocellar triangle, and a large triangular macula on the front, brown pilose, pile on front black, on gena and face white pilose, on ocellar triangle black pilose, on the occiput white except the dorsal pile, which are black, frontal triangle golden metallic; face with a carina above the tubercle. Antennae brown, rounded, as long as wide, ratio 1.1:1.2:2; arista orange, dark brown toward the tip. Thorax (Fig. 10B, C). Black, the scutum shining, with iridescent to opaque reflections, with two median brownish pollinose vittae on anterior half. Wing (Fig. 10D). Slightly smoky, the stigma brown, membrane extensively microtrichose, except for extensive bare areas on basal half (cells, sc, r1, dm, and bm); costal cell brownish, extensively microtrichose; tegula black pilose, basicosta yellow pilose, alula extensively microtrichose; calypter whitish, border whitish, fringe yellow, plumula yellow, halter yellow, knob white. Legs (Fig. 10C). Dark brown, pro-and mesofemur brown, orange on apical 1/8; metafemur extensively brown; pro and mesotibiae orange with a brown macula on posterior medial edge, metatibia extensively brown, only orange brownish on basal 2/3; tarsi brown, only meso-basitarsi orange basally, the pile yellow, black on the metatibia and above on the tarsi. Abdomen (Fig. 10B). Elongate, black, first tergum shining black, second with a pair of small narrow maculae, occupying 2/5 of segment length, third and fourth with basomedial maculae, reaching 2/5 and 1/5, respectively. Pile orange on the sides basally, black down the middle and on the apical terga, as well as in the maculae; sternite IV black pilose. Male genitalia as Fig. 11.
Female. (Fig. 10D-F). As male, except for usual sexual dimorphism and following differences: frons with a pollinose transversal macula below. Abdomen with a pair of square-like and apically rounded maculae on the second tergum, which occupies the anterior half of the tergum and comparatively larger than in the male. Profemur extensively yellow on anterior half. Female of Argentinomyia talamanca is similar in appearance to Argentinomyia puntarena sp. nov. but in A. puntarena the antenna is orange ventrally; alula and costal cell bare; pro, meso-and metabasitarsomere I-II yellow; second tergum with a lateral macula reaching the 5/6 of tergum length.
Etymology. The noun in apposition 'Talamanca' refers to the cordillera where the species was collected in Costa Rica.

Genus Talahua Fluke
Redescription (modified from Fluke 1945: 22, andMengual 2014). Body size. Large-sized flies, 9-12 mm. MALE. Head (Fig. 13A-C, E). Face large, shining black, wider than the thorax and abdomen, straight to perpendicular, not produced, with a large well-rounded tubercle (low dorsally, not distinct in some Argentinomyia), densely pollinose, sides of face usually with coppery reflections and a faint, slightly rugose area; front not swollen; gena large; oral tips, ocellar triangle, and the large triangular macula on the front shining black; pile on front generally black, on gena and face yellow to white, on ocellar triangle black, on the occiput yellow except the dorsal pile black; eyes bare, holoptic in male, with eyes contiguity as long as ocellar triangle; antennae black, pedicel and the lower basal corner of basoflagellomere red, short, scape broader than long, nearly equal to pedicel, basoflagelomere large, rounded or oval, ratio 1.1:1.5:2.5, arista black, dorsobasal, as long as the basoflagellomere or more, bare. Thorax (Fig.  13A-F): Black; postpronotum (humerus) bare; notopleuron with distinctive tubercle; scutum shining, covered with yellow pollen and short golden pile with many longer black pile that appear yellowish at the base, these pile become longer posteriorly; pleura yellow pollinose and pilose; scutellum black and with transversal rugose area on the disc, generally with longer yellowish and black setae on the posterior margin; subscutellar fringe complete, with multiple rows yellow pile; postmetacoxal bridge incomplete; pleura black to orange, whitish pollinose and pilose. Legs (Fig. 13C). Black; profemora yellow on the apical 1/3, mesofemora yellow on the apical 1/3, metafemora yellow on the apical 1/3; all the tibiae yellow with a dark ring near the middle, more prominent on the metatibia; tarsi brown, the pile yellow, black on the metatibia and above on the tarsi. Wing (Fig. 13A-F). Smoky; membrane entirely microtrichose, except for extensive bare areas on basal half (cells c, sc, r 1 , dm, and bm); the stigma and costal cell brownish; vein R 4+5 straight; vein M 1 (apical crossvein) oblique, slightly sinuous; alula broad, broader than cell cup, extensively bare,; calypter yellow, plumule simple, yellow; halter yellow, with a darkened capitulum. Abdomen (Fig. 13B-F). Elongated, black, with parallel sides, as broad as or broader than thorax, segments more or less quadrate, as long as broad, without premarginal sulcus, markings on tergites variable, with four pairs of lateral rounded to triangular prominent yellow maculae or with a complete basomedial black maculae; the first tergum shining, second with broad lateral yellow and only the apex black, third tergum with similar but wider maculae, fourth tergum with still wider but less elongate maculae, fifth tergum with a pair of small maculae in the basal corners. Pile yellow on the sides basally, black down the middle and on the apical terga. Male genitalia as Figs 12E, 14.
Female. (Fig. 13C-E). Similar to male except for normal sexual dimorphism. Abdominal maculae are comparatively shorter than in the male. Front narrow above, not the much wider than the ocellar triangle, shining above with a pollinose transversal macula below. Sixth tergum with a pair of small basolateral maculae. Sterna extensively yellow, yellow pilose, only brownish pilose in the apical corners of sterna four to sixth.
Distribution. Talahua fervida is exclusively restricted to the Tropical Andes of Central and Occidental Cordillera in Colombia (Antioquia, Boyacá, Cundinamarca, Tolima) to Central Cordillera in Ecuador (Bolívar, Sucumbios). The species has a mountainous distribution in the biogeographical provinces of Cauca, Magdalena and North Andean Páramo (Fig. 17).  Ecology. Adults of Talahua fervida are found in highland ecosystems including cloud forests of the Andesand Páramo from 1800 to 3350 m a.s.l. The species has been associated with flowers of Clusia cf. brachycarpa Cuatrec (Clusiaceae Lindl.), but the immature stages are unknown.

Discussion
The new Argentinomyia species described here can be distinguished from its congeners by the combination of the following characters: the basoflagellomere large, slightly oval and apically rounded; face with a well-rounded tubercle, never with transversal grooves dorsally along tubercle or broadly punctuate laterally; scutellum with a deep groove next to the rim (emarginate); metacoxa with pile posteromedial on apical angle; abdomen elongated or parallel sides with large markings. Talahua fervida differs from the new species by having the male genitalia large, including the surstyle, superior lobes, and cerci elongated, character recognized by Fluke (1957) and Thompson (1999) as exclusive for Talahua.
The new Argentinomyia species described here as well as Talahua fervida inhabit the Andean cloud forests and Páramo in Mesoamerica (México and Costa Rica) and Tropical Andes (Colombia and Ecuador) including five biogeographical provinces, which have been commonly referred to as hotspots of biodiversity (Maps 1, 2 and 3) (Myers et al. 2000). The distribution patterns suggest the existence of new endemic species in the highlands of neighboring countries.
Their restricted distribution, the local abundance and the fact that most species inhabit Protected and Conserved Areas suggest their vulnerability as proposed for several syrphid groups (see Montoya et al. 2012, Morales et al. 2013. This, besides the fact that many of these areas are facing anthropogenic pressures such as deforestation by mining, and wood extraction, indiscriminate and constant application of herbicides and pesticides, as well as the loss of biological corridors derived from the construction of hydroelectric and roads, highlight the risk for the survival of these species, as well as the maintenance of ecosystem services they provide. In consequence and given that only one Neotropical species has been assessed in the IUCN Red List (Alaniz et al. 2018, López-García et al. 2019, there are compelling reasons to propose the new species as well as Talahua fervida as flagship entities for the conservation of the areas where they occur, been critical as environmental quality bioindicators. We considered that the information provided will constitute a baseline to assess their conservation status following the guidelines of the International Union for Conservation of Nature (IUCN).

Acknowledgments
Thanks are due to F. Christian Thompson (Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington D.C., USA) for his continuous support to my formation and for allowing me to study the flower flies housed in the USNM collection. I'm very thankful to the collection curators and researchers, in particular to Philippe Sagot for facilitating access to the material to his cure. I sincerely thank Torsten Dikow for all the valuable help during my internship at the Smithsonian Institution. Thank are due to everyone who collects this invaluable material, especially to the members of the Entomology Group, University of Antioquia (GEUA). This study was supported by funding provided by the FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA LA TECNOLOGÍA Y LA INNOVACIÓN "FRANCISCO JOSÉ DE CALDAS" and COLCIENCIAS (Convocatorias 712-2015(Convocatorias 712- , 745-2016 to the project "Las moscas de las flores (Diptera, Syrphidae) como bioindicadoras de la calidad del ambiente en los ecosistemas altoandinos del noroccidente de Colombia" and COLFUTURO Ph.D. Grant (Becas Colciencias Doctorados Nacionales, convocatoria 647 de 2014). The project was partially financed by a grand of the GLOBAL GENOME INITIATIVE, Grant Number: 801-0000-302357-332002-6100-XXXX-4120-33GGI2018GRANTE-BUENAVEN-TURAE. Thanks are also due to the Samuel Wendell Williston Diptera Research Foundation for financial assistance to attend the 8 th International Congress of Dipterology in Potsdam, Germany, where the first advance of this work was presented. Thanks are due to Ximo Mengual and the reviewers Andrew Young and Menno Reemer for helpful comments and suggestions that enriched the manuscript. Thanks to Elizabeth Orozco García for all her support, dedication and for teaching me to fly to achieve my dreams, you are unique. Special thanks to Paula Rozo, who contacted me with Juanita Roca and Álvaro Espinel, who kindly welcomed me at their home during the internship in Washington D.C. and made this experience productive and unforgettable.