Review of the genus Euantha Wulp, 1885 (Diptera: Tachinidae), with key to species and redescription of E. pulchra Wulp, 1891

Abstract Euantha Wulp is a New World genus in the tribe Sophiini (Dexiinae). It includes three species: E. interrupta Aldrich, 1927, E. litturata (Olivier, 1811) and E. pulchra Wulp, 1891. This last species is poorly known, being restricted mostly to catalogues since its original description. Here E. pulchra is redescribed, a lectotype is designated and the male is diagnosed for the first time. In addition, this species (originally described from Mexico) is newly recorded from Guatemala. Finally, the first key to include all the species of Euantha is provided.

Euantha pulchra is poorly known and has not been studied since its original description from Mexico by van der Wulp (1891).It has only been included in catalogues (Guimarães 1971) and lists (O'Hara et al. 2020), in addition to Guimarães' revision of the sophiines (1982) as synonym of E. litturata; however, it was not included in any species key and its identity has remained uncertain.In this paper, E. pulchra is redescribed based on the type series and additional specimens, including the male for the first time.A lectotype is designated from among the three existing female syntypes to fix the name to a single specimen in accordance with Article 74 of the Code (ICZN 1999), that pertains to the purpose of fixating the identity of the name to the respective name-bearing specimen, to clarify any taxonomic doubt involving that name.The first identification key for all species of Euantha is also provided.

MATERIALS AND METHODS
The examined material is deposited in the Natural History Museum, London, UK (NHMUK).The label data are presented within quotation marks for each label, with forward slashes indicating line breaks and semicolons separating different labels.Comments about labels, additional information and corrections are given in square brackets.Morphological terminology follows Cumming & Wood (2017).

Key to species of Euantha
Paralectotypes: two females (NHMUK), same locality data as lectotype, and conspecific with the lectotype.A green label written "Paralectotype" was added to each specimen.Van der Wulp (1891) described this new species based on five female syntypes, that should all be in NHMUK but only three female syntypes were found.
Diagnosis.Vein R 4+5 without appendage at bend; abdominal tergites with silvery pruinose bands on females, and yellowish on males, not interrupted in middle; legs with femur yellowish, but on about ⅛ on distal region is brownish black.

Redescription of female
Body length: 12.5 mm.
Coloration (Figs. 1a-d) Occiput with silver pruinosity; with long golden setae.Fronto-orbital plate blackish, but external portion, about ¼ silvery pruinose.Parafacial, face and gena silvery pruinose.Genal dilation light brown.Antenna dark brown.Arista light brown.Palpus dark brown.Labellum and prementum dark brown.Thorax laterally dark brown, but silvery pruinosity on anepisterum and katepisternum.Scutum silvery pruinose with two broad brownish black vittae.Postpronotal lobe with silver pruinosity.Scutellum dark brown, but silvery pruinose on distal half.Subscutellum and postnotum dark brown.Tegula and basicosta dark brown.Wing hyaline, but with dark markings on subcostal and costal distal cells and distal portion of cells r₁, r₂₊₃ and r 4+5 , and darker along the veins.Calypters whitish.Halter with knob dark brown and stalk light brown.Legs dark brown, but coxae with silver pruinosity and femur yellowish, but on about ⅛ on distal region is brownish black.Claws dark brown.Abdomen brownish black, but tergites III and IV with a broad band of white pruinosity on about ¾ of anterior margin, extending down to the sides; tergite 5 with silver pruinosity dorsally.
Fronto-orbital plate with 2 proclinate and 1 lateroclinate orbital setae.Parafacial bare.Width of parafacial measured at distance between inner margin of eye and antennal insertion 2.5X the gena height.Postpedicel slender, 1.5X the length of scape and pedicel combined; arista long plumose.Facial carina present.Facial ridge setulose on lower third (near vibrissa insertion).Lower facial margin not protruding, and not visible in profile.Genal height about 2.5X the eye height.Vibrissa long, inserted at level of lower facial margin.About 5 subvibrissal setae.Labella well developed, about half the length of prementum, which is about the same length as palpus.
Male.Differs from female by the following.(Figs.2a-c): without orbitals on the fronto-orbital plate.Postpedicel with proximal half orange and distal half light brown.Head, thorax and abdomen with golden pruinosity.Prescutum pale silvery pruinose, with four brownish black vittae, the outer four times the width of the inner.Scutellum pale golden pruinose.Claws and pulvilli longer than the female.
Remarks.In the same work, van der Wulp (1891) additionally recorded two males and six females as Euantha dives (Wiedemann, 1830) [(=E. litturata (Olivier, 1811)].However, MDS's examination of Wulp's material at NHMUK revealed that three males identified as Euantha dives by Wulp are, in fact, males of E. pulchra and are treated as such herein.Furthermore, Aldrich (1927) also noticed that van der Wulp (1891) wrongly mistook some males of E. dives (=E.litturata) as females, having concluded that E. pulchra would be a synonym of E. litturata, a position also maintained by Guimarães (1982).While it is confirmed herein that Wulp mistook the gender of those specimens, the synonymy cannot be maintained.Guimarães (1971), and later O'Hara et al. ( 2020) treated E. pulchra as valid, but Guimarães (1982) listed it as a synonym of E. litturata without giving an explanation for this change in status.However, based on our comparisons with other species of Euantha, we confirm that E. pulchra is a valid and distinct species.