SEM studies and discovery of an intriguing new Rhamphomyia (Pararhamphomyia) (Diptera, Empididae, Empidinae) species from the Kashmir Himalayas

Abstract

Here we present an intriguing new species of the Empididae genus Rhamphomyia (Pararhamphomyia) from the Kashmir Himalayas. The new species, Rhamphomyia (Pararhamphomyia) aquila, has a distinctive appearance due to its highly deformed male hind legs with extremely shortened hind tibia, a feature very peculiar in the genus. The new species is described along with elements of mating behaviour, the mechanism of male hind leg articulation, and its possible role during mating. Also, scanning electron microscopy analysis is used to elucidate the general morphology and sensilla in both sexes of the new species. Details of the male and female internal reproductive system are described and illustrated. A preliminary checklist of 55 species of the Empididae of India is provided.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:A28B850F-6A2D-4FB2-9AC3-E89015C1C5A7

http://www.zoobank.org/urn:lsid:zoobank.org:act:C0249B1D-D0C8-4998-96A2-C25D3DB89810

Keywords:

• Taxonomy
• Rhamphomyia
• new species
• distribution
• India
• hind tibia
• Kashmir Valley

1. Introduction

The genus Rhamphomyia Meigen, 1822 (Diptera: Empididae) is widespread across multiple zoogeographical regions (Saigusa 2012), and currently about 610 species are known worldwide (Rhodén & Wahlberg 2020). These are important pollinators in high mountains and in boreal environments (Barták & Kubík 2009); they are also important biocontrol agents and important bioindicators (Grootaert et al. 2000). So far most of the species have been reported from the Holarctic Region, with some unpublished estimates suggesting the richest diversity to be present in the Nearctic (Barták & Kubík 2009; Sinclair et al. 2019). Globally it is estimated that there may be as many as 1500 species of Rhamphomyia (Sinclair et al. 2019). The genus consists of several subgenera which helps provides a better overview of its diversity (Rhodén & Wahlberg 2020). The first attempt at subgeneric grouping was carried out by Frey (1909, 1922), and recent papers by Barták (1981, 1982), Chvála and Wagner (1989) and Saigusa (2012) remain very relevant in this regard. Currently, the genus consists of about 18 subgenera (Yang et al. 2007; Barták & Kubík 2009; Saigusa 2012), almost exclusively relevant for the Palaearctic fauna; some of those that were revised recently are stable, while others remain problematic and include the presence of extralimital species (Rhodén & Wahlberg 2020; Barták et al. 2021). The use of plesiomorphic characters for subgeneric classification, the probable polyphyletic nature of the genus and its high diversity, among not only the congeners but also the allied genus Empis L., has made the current subgeneric classification unreliable (Saigusa 2012; Chvála & Pont 2015). A global comprehensive review to delimit, establish and redefine subgeneric classification and overall diversity of the genus has yet to be performed.

The subgenus Pararhamphomyia Frey, 1922 includes about 120 species, mostly known from the eastern parts of the Palaearctic Region (Barták & Kubík 2009), but surely diverse in the Nearctic Region as well. These species are characterised by the prosternum and mostly propleura without setae, biserial acrostichals, incomplete anal vein, long setose labella and usually a distinct basal costal seta. The separation of Rhamphomyia s. str. and Pararhamphomyia remains sometimes rather difficult but can be resolved using the decision table provided by Barták (1982).

We provide a description of a new species belonging to Rhamphomyia (Pararhamphomyia) from the Kashmir Himalayas (India). The species placement within the subgenus Pararhamphomyia follows Collin (1961) and Barták and Sinclair (2003). Within the subgenus Pararhamphomyia, the placement of the new species and its association with known species groups remains unclear. With the presence of joint distortion in the male hind leg, the new species can be placed in the basalis species group, but the male terminalia, especially the shape of the cercus and the absence of a subepandrial lobe, do not match those of the basalis group (see also Chillcott 1959). The male terminalia, particularly the shape of the cercus, is more similar to that of the members of the pusilla group – from which, however, there are also marked differences (see Remarks). The new species is the fourth Rhamphomyia species to be discovered from India (Brunetti 1913, 1917, 1920; Barták et al. 2021).

In addition to description of the male and female specimens elucidated with scanning electron microscopy (SEM) analysis, a discussion on the mating behaviour is provided including a possible role for the modified male hind leg. We also include details of the male and female internal reproductive system and compare them with those of the other recently discovered Rhamphomyia species from India. The comparison suggests the possible use of the male internal reproductive tract as a species-specific character (see Discussion).

2. Materials and methods

2.1. Materials, light and scanning electron microscopy

Specimens were collected by net sweeping and hand picking from the fruit orchards of the Central Institute of Temperate Horticulture (CITH) during the years 2015–2021. CITH is situated at 33.59°N, 74.50°E, at an altitude of 1640 m a.s.l. (Figure 1). The field photographs were obtained using a Canon 80D DSLR fitted with a 100 mm macro lens. Taxonomic analyses were conducted using an Olympus SZX16 stereo zoom microscope. For digital images, ProgRes0 Capture Pro v. 2.8.0. evolution digital camera was used on the same microscope with Combine ZP-Montage software. Later, images were cleaned up with Adobe Photoshop CS6. Genitalia together with 2–3 pregenital segments were removed and macerated in potassium hydroxide solution (10%) in small vials, for 1–2 h, treated with 8% acetic acid and dissected in glycerine. For bright-field microscopy, prepared slides were placed on a stage prepared from cardboard and provided with an LED lamp (3 W) to produce the transmission light beam. For dark-field microscopy a dark-field illumination filter was used to illuminate unstained specimens. Microphotographs were captured with a digital mirrorless camera (Nikon Z50) with attached infinity-corrected microscope objectives (Lomo 3.7× and Nikon CFI Plan Achromat 10X). The details and description of the type locality and the illustration procedure are similar to those of Barták et al. (2021).

Figure 1. (a, b) Type locality of the new species, Central Institute of Temperate Horticulture, Srinagar, Jammu and Kashmir, India.

The morphological terms used here follow Sinclair and Cumming (2006). All the specimens are deposited in the Central Institute of Temperate Horticulture Insect Collection, Srinagar (CITH). Two paratypes will be deposited in the Natural History Museum, London, UK (NHMUK), four at the Czech University of Life Sciences Prague (CULSP) and two at the University of Silesia, Katowice (DZUS). For studies on leg articulation, the dissection procedure described by Földvári et al. (2019) was followed. Ethanol-stored specimens were bleached and rehydrated in 35% H₂O₂ for 24 h and then transferred to anhydrous glycerol. Specimens were dissected in glycerol with fine forceps, insect pins and razor blades on concave slides. The straightening and bending movements of the leg were observed to understand interaction between the proximal tibial flexor tendon and the ventral femoral wall. For this the bleached legs were moved with insect pins; these pins were also used to dislodge the locking sclerites, similarly to Földvári et al. (2019). The term “sclerite” was used for less flexible areas of the exoskeleton that are connected to each other by more flexible conjunctiva, as detailed in Klass and Matushkina (2012) and Ronquist and Nordlander (1989). All the procedural videos were taken with the use of a camera attached to the microscope and are provided as supplementary files. Specimens for SEM analyses were preserved in 70% ethanol for several days, processed as described by Barták et al. (2021) and imaged with the Hitachi SU8010 field emission scanning electron microscope (FESEM; Hitachi High-Technologies Corporation, Tokyo, Japan), Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, in Katowice.

2.2. Institutional abbreviations

CAU	=	China Agricultural University, Beijing, China
CITH	=	Central Institute of Temperate Horticulture, Srinagar, India
CULSP	=	Czech University of Life Sciences, Prague, Czech Republic
DZUS	=	University of Silesia, Katowice, Poland
MZLS	=	Musée cantonal de zoologie, Lausanne, Switzerland
NHMUK	=	Natural History Museum, London, UK
PAN	=	Polish Academy of Sciences, Warsaw, Poland
ZFMK	=	Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany
ZIN	=	Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia
ZSI	=	Zoological Survey of India, Kolkata, India

3. Results

3.1. Taxonomy

Rhamphomyia (Pararhamphomyia) aquila sp. nov.

(Figures 2–13)

Figure 2. Rhamphomyia aquila sp. nov., male. (a) Head, frontal view; (b) habitus, lateral view; (c) habitus, dorsal view.

Figure 3. Rhamphomyia aquila sp. nov., male. (a) Mouth parts; (b) antennae; (c–d) legs, male hind leg with deformed femorotibial joint, enlarged view; (e) fore and mid legs; (f) male fore wing with labelled discal cell (dm), cubitus (CuA1) and medial veins (M2); (g–h) male genitalia, cercus (cerc), ejaculatory apodeme (ej apod), epandrium (epand), hypandrium (hypd), phallus (ph).

Figure 4. Rhamphomyia aquila sp. nov., female. (a) Head, frontal view; (b) habitus, lateral view; (c) habitus, dorsal view.

Figure 5. Male and female internal reproductive system of Rhamphomyia aquila sp. nov. (a–d) female internal reproductive tract: (a–b) complete internal reproductive system; (c) right ovary removed and spermatheca extended; (d) separated spermatheca, enlarged view. (e–f) male internal reproductive tract.

Figure 6. Scanning electron microscopy showing general morphology of (a) female and (b) male of Rhamphomyia aquila sp. nov. body, lateral view; (c) female head, full face view; (d) male head, full face view; (e) female terminalia; (f) male terminalia.

Figure 7. Scanning electron microscopy of Rhamphomyia aquila sp. nov. female head and antennal sensilla. (a) Dichoptic eyes; (b–c) mouth parts with palpi bearing 3–4 long setae (white arrow); (d–e) labium and long stylet labrum with epipharyngeal blades; (f) ventral side of postpedicel with sensilla (white arrows); (g–i) basiconic sensilla (most probably type I) (white star); (j–l) sensilla basiconica with granulated and porous surface.

Figure 8. Scanning electron microscopy of Rhamphomyia aquila sp. nov. male head and antennal sensilla. (a–b) Holoptic eyes, with enlarged facets along dorsal half; (c–d) labellum with distinct pseudotracheae; (e) sponge-like general surface of pseudotracheae; (f) labrum with piercing, serrate apical part (white arrows); (g) expanded and convex ventral basal of postpedicel with basiconic sensilla (arrows); (h–k) regularly arranged basiconic sensilla with swollen bases and small pores of sensilla ampullacea (white arrows); (l–o) stylus, mechanoreceptor porous with dense covering of microtrichia.

Figure 9. Scanning electron microscopy of Rhamphomyia aquila sp. nov. male antennal sensilla. (a) Basal portion of postpedicel with group of sensilla coeloconica (dotted box); (b) regularly placed sensilla coeloconica (arrows); (c–e) sensilla coeloconica located in depressions (white star); (f–h) peg-shaped sensilla coeloconica surrounded by ring-like cuticular elevation (white dotted arrows).

Figure 10. Scanning electron microscopy of Rhamphomyia aquila sp. nov. male detailing wing articulation. (a–c) Microtrichia wing membrane with wax layer; (d–f) long, ribbed chaetic sensilla present along wing edges.

Figure 11. Scanning electron microscopy of Rhamphomyia aquila sp. nov. halter. (a–b) Ventral and dorsal side of the halter with robust scabelum, pedicellus and oval capitellum; (c) sensilla on dorsal scabellum and dorsal pedicellus; (d) scabellus protuberant basal plate sensilla; (e) oriented flanking sensilla on the dorsal pedicel stem; (g–k) single trichoid and campaniform sensillum on capitellum (black arrows : solid, dotted), in addition to the general dense microtrichia.

Figure 12. Scanning electron microscopy of Rhamphomyia aquila sp. nov. legs. (a–b) Swollen male hind femur and extremely reduced hind tibia; (c–g) long and stout trichoid and chaetic sensilla on apical third of femur, posteroventrals; (h–j) single campaniform sensillum on the basal inner side of femora (arrow) with small pore near the centre (star); (k–l) elongate basitarsus with large grooved chaetic sensilla; (m–n) trichoid and chaetic sensilla on third tarsomere; (o–q) curved claws and pulvilli (r) fine structure of tenent setae and terminal plates.

Figure 13. Scanning electron microscopy of Rhamphomyia aquila sp. nov. male and female genitalia. (a) Terminal female abdomen tergites; (b) in ventral view appear partially retracted into proximal segment; (c–e) seventh and eight segments of abdomen with longer chaetic sensilla dorsally; (f) thick, long chaetic sensilla of cerci; (g) smooth basal part of phallus; (h–i) long and rigid chaetic sensilla on genitalia; (j–l) phallus broad, covered by waxy secretions, and bulb-shaped apical portion (arrow).

Diagnosis

Black species of Rhamphomyia (Pararhamphomyia): legs and body setae black, black palpus, acrostichals biserial, dorsocentrals irregularly biserial and much longer than acrostichals; halter yellow, anal lobe well developed with rectangular axillary angle, anal vein incomplete. Male with deformed hind femorotibial joint having tuft of anteroventral bristles; distinctly shortened hind tibia; epandrium subtriangular, truncate, cercus with broad base, tapered at mid-length to truncate apical portion, phallus lustrous with apex having shallow S-shaped curvature.

Material examined

Holotype. ♂, INDIA: Kashmir: Srinagar: Central Institute of Temperate Horticulture, 34.0094°N 74.7984°E, 1640 m.a.s.l., 1 May 2017 (CITH). Paratypes. Same locality as holotype, except: 12 May 2015 (5♂, 8♀, CITH), 28 April 2016 (2♂, 2♀, CITH), 1 May 2017 (13♂, 20♀, CITH), 6 May 2017 (2♂, 2♀, CITH), 11 June 2018 (8♂, 19, CITH), 7 May 2019 (10♂, 13♀, CITH), 15 April 2020 (11♂, 9♀, CITH), 21 May 2020 (3♂, 6♀, CITH), 3 April 2021 (9♂, 2♀, CITH), 8 May 2021 (15♂, 15♀, CITH), Shahid Ali Akbar leg.

Distribution

India (Jammu and Kashmir).

Date of occurrence

April to June.

Description

Male (Figures 2–3). Head with pale greyish pruinescence on face, frons, postgena and occiput; eyes holoptic, meeting along median dorsal line, facets in dorsal half of eye considerably enlarged (Figure 2a); frons represented by small triangular space below ocellar tubercle and larger sub-triangular space above antennae, brown, without setulae; face parallel sided, slightly converging dorsally near antennae and divergent towards mouthparts; approx. 0.11–0.14 mm wide, 0.15–0.18 mm long, without setae; microtrichose with pale greyish pruinescence, labrum microtrichose. Gena narrow and microtrichose. Palpus black and short, with several long setae (up to 0.22 mm). Labrum black, shiny, almost as long as head height; labellum with rather long setae (Figure 3a). Ocellar triangle dark brown pruinescent, ocellar setae black, fine, approximately 0.11–0.15 mm long, accompanied by several smaller setulae. Occiput with row of dark, fine postocular setae on upper half of occiput similar in length to ocellars; remaining occipital setae shorter; postocular row incomplete, irregular on lower half. Antenna black, both basal segments short, setose; length of antennal segments (scape:pedicel:postpedicel:stylus) = 0.05–0.07 mm:0.04–0.05 mm:0.22–0.25 mm:0.05–0.06 mm; postpedicel conical, 2.3–2.5× longer than wide (Figure 2a, 3b).Thorax pale greyish pruinescent. Thoracic setae dark, posterior dorsocentrals, postalars and scutellars black; acrostichals and dorsocentrals also dark black (Figure 2b–c). Chaetotaxy: antepronotum with numerous fine setae; postpronotum with 1 long seta and additional 3–4 short dark setae; proepisternum with 2–3 stout, dark setae; upper proepisternum in front of spiracle with 2 setae; prosternum and propleura bare; acrostichals biserial and few in number (6–8 in one row), about 0.10–0.14 mm long; dorsocentrals irregularly biserial, slightly longer than acrostichals, ending in 2–3 long, black prescutellar pairs; 1 presutural intra-alar (intrahumeral), 1 presutural supra-alar (posthumeral) and additional 1–2 dorsocentral setae; 2–3 notopleural setae and 1–2 rather long but fine setae on anterior part of notopleuron; 1–2 supra-alars and 1 small prealar; two pairs of black scutellars.

Legs

Black to dark brown, microtrichose, with black setae (Figures 2b–c, 3c–e). Fore femur with sparse rows of very short anteroventrals and somewhat longer posteroventrals (about half as long as femur depth), dorsal setae shorter. Fore tibia with very short setae, posteroventrals fine and about as long as tibia depth. Mid femur with anteroventral row of setae slightly shorter than femur depth and similar row of posteroventrals, shorter on proximal part, on distal part with several slightly stronger setae, dorsal setae short. Mid tibia with short and fine dorsal setae, only 1–2 antero- or posterodorsals slightly longer than tibia depth, ventral setae stronger, almost spine-like, arranged in two rows, subequal in length to tibia depth. Hind femur with row of strong preapical setae; strongly modified (Figures 2 b–c, 3c–d): swollen, with long ventral protuberance on basal third to half and strong ventral incision on apical third, on apical third with long ventral setae and comb of posteroventrals, dorsally with short setae. Hind tibia extremely shortened, roundly expanded at base, with dorsal knob, with several strong and long setae. Hind basitarsus extremely elongate, strongly constricted on basal third, much longer than tibia, covered with dense short slightly widened setae on both sides. Tarsi of both fore and mid legs narrow with short setae, with apical circlets of setae and long claws. Posteroapical comb of hind tibia with 1 long seta.

Wing

Clear, veins brownish-black, pterostigma brown, anal vein incomplete; anal lobe well developed with rectangular axillary angle. Halter yellow with brown stem, calypter yellow with whitish fringes (Figure 3f).

Abdomen. Abdomen silvery pruinescent; with short black setae, finer and longer on proximal tergites, stouter and shorter towards terminalia (Figure 2b, c). Lateral marginal setae on tergites 2–4 longer, dorsal setae much shorter, sternites with uniform long, light brown setae. Sternite 7 produced ventrally. Sternite 8 larger than sternite 7, closely appressed laterally with tergite 8; with long setae posteriorly. Tergite 8 half length of sternite 8 with short marginal setae. Terminalia dark grey, barely longer than abdominal width. Epandrium subtriangular, truncate; apex of epandrium down-curved with tuft of long setae; inner apex thinly sclerotised with short setae. Cercus with broad base, strongly attenuated at mid-length; dorsal margin of cercus bearing many short, fine, erect dark setae. Hypandrium ending in middle of swollen phallus base; phallus lustrous, reddish brown, gently arched between epandrial lamellae; apex with shallow S-shaped curvature. Ejaculatory apodeme fan-shaped with lateral wings shorter than vertical wing (Figure 3g–h).

Length

Body 4.0–5.0 mm, wing 3.5–4.2 mm.

Female (Figure 4). Similar to male, but body setae much shorter and lighter; legs simple and unremarkable, without deformed hind femorotibial joint. Eyes dichoptic with all facets almost equal in size (Figure 4a). Frons approximately 0.14–0.18 mm, broad with 4–5 black, rather long setae on sides. Labrum black, labella with rather long setae. Thoracic chaetotaxy: acrostichals and dorsocentrals black, dorsocentrals distinctly longer. Both fore and mid femora with short setae, longest (distal) posteroventrals shorter than femur depth. Both fore and mid tibiae very short, without prominent setae. Hind femur short, anteroventral setae and prominent posteroventrals, shorter than femur depth. Antero- and posterodorsal setae of hind tibia as long as tibia diameter (Figure 4b–c). Length: body 3–3.3 mm; wing 3.1–3.4 mm.

Female and male internal genital tract (Figure 5). Internal reproductive tract of female comprises paired ovaries, lateral oviducts, common oviduct, long tubular vagina, spermatheca, spermathecal duct and two accessory glands (Figure 5a–c). Vagina appears as elongate muscular tube lined internally with thin cuticle; anteriorly fused with common oviduct. Spermathecal duct and ducts of accessory glands open anterolaterally and posterolaterally, respectively, into vagina. Ovaries broad leaf-like with four follicular cell layers, with youngest oocytes near apical germarium and most mature ones near basal region. Eggs empty into lateral oviducts, unite into common oviduct. Spermatheca with broad basal stalk, extending into elongate duct and terminating as round reservoir for sperm mass collection and storage (Figure 5d). Accessory gland appears as small bisected delicate sacs, with thicker basal sac compared with thinner apical sac.

Internal reproductive tract of male comprises paired testes, vas deferens, pair of accessory glands and common ejaculatory duct (Figure 5e–f). Each testis bulb-shaped, comprising testicular follicles enclosed in common outer sheath. Vas deferens appears as long tube-like structure, without enlarged and differentiated region distinguished as seminal vesicle. Tubular accessory gland ducts along with vas deferens open into anterior portion of ejaculatory duct. Ejaculatory duct short without distinct folds.

Etymology

The species epithet is Latin for eagle and appropriately symbolises the aerial grabbling skills and holding dominance of the male specimens of the new species.

3.2. Notes on SEM morphology of Rhamphomyia aquila sp. nov. (Figures 6–13)

The male is generally similar to the female, except for the normal sexual dimorphism. Variations in general morphology, eyes and terminalia can be observed (see Figure 6).

3.2.1. Head, antennae and mouthparts

In females, the ommatidia are tightly and regularly deployed (20–25 μm), uniform without dimorphism between the upper and the lower halves (Figure 7a). The palpi are long, cylindrical, rarely strongly compressed laterally (Figure 7b), bearing 3–4 long setae, in addition to fine microtrichia throughout (Figure 7c). Labium with dense cover of microtrichia and several thick, long chaetic sensilla along the dorsal side of the labellum (Figure 7d). Labrum is long. The stylet is covered by a wax layer, with pointed epipharyngeal blades (Figure 7d, e). The antennae are rather short. Scape, pedicel, postpedicel and stylus are covered by numerous fine sclerotic microtrichia and several types of sensilla especially on the ventral side of the postpedicel (Figure 7f). Most of the basiconic sensilla (most probably type I) are located along the ventral side of the postpedicel, placed regularly, lengthwise (Figure 7g, h). They are 5–9 μm long, sometimes covered by a wax layer. Some sensilla are characterised by a multiporous surface (Figure 7i, j), whereas others have rather grooved surfaces (Figure 7k, l).

In males, the ommatidia of the compound eye exhibits distinct dimorphism with a larger upper half and smaller lower half, tightly and regular deployed (Figure 8a, b). The distinct pseudotracheae channels and ground surface of the labellum provide capillary action (Figure 8c, d), whereas the proximal part of the labellum is characterised by a very granular surface (Figure 8e). The labrum has an array of rasps and teeth on the apical part of the epipharyngeal blades, used for piercing (Figure 8f). The antennae are similar to those of the female, and most of the sensilla are located on the ventral side of the postpedicel, a larger segment having an expanded and convex ventral basal part (Figure 8g). The postpedicel is densely covered by prominent microtrichia and numerous, regularly arranged basiconic sensilla (Figure 8h). The basiconic sensilla are located in depressions and characterised by a wide and rounded basal part, and they are mostly without a porous surface (Figure 8i, k). On the cuticle of the postpedicel some small pores of sensilla ampullacea are also apparent (Figure 8i, j). The stylus has a dense covering of microtrichia with the most apical part bare (Figure 8l). The sensillum surface of the apical part of the stylus seems to be smooth but at higher magnification it is clear that the cuticle is covered by numerous longitudinal pores (Figure 8m–o). The basal portion of the male postpedicel latero-ventrally consists of numerous regularly placed sensilla coeloconica, located in deep depressions and surrounded by a large ring-like cuticular collar (Figure 9a–c). The sensilla are visibly tapered with a wider basal part and a more pointed distal part (Figure 9d, e). On the other hand, the lateral side of the postpedicel bears more sensilla coeloconica characterised as a raised peg with terminal bulb-like tip and 6–7 well-visible projections (Figure 9f–i).

3.2.2. Wings

Wings in males and females are similar, with a distinct wax layer and a microtrichose wing membrane, regularly deployed, fine, slightly pointed and slightly ribbed. The wing edges and wing articulation bear chaetic sensilla, long and ribbed with basal groove raised (Figure 10). The halter is covered by numerous microtrichia with robust scabellum, with well-visible sensilla plates, pedicellus and oval capitellum (Figures 11a, b). Sensilla on the dorsal scabellum and dorsal pedicellus distinct (Figure 11c), scabellus with densely arranged spherical and protuberant basal plate sensilla (Figure 11d), and similar linearly oriented flanking sensilla on the dorsal pedicel stem (Figure 11e); flanking sensilla are also well marked on the ventral pedicellum (Figure 11f). The capitellum is characterised by a single trichoid and campaniform sensillum along the ventral side and single prominent trichoid sensillum along the dorsal in addition to the general dense microtrichia (Figure 11g, k).

3.2.3. Legs

Legs in males and females are densely covered by numerous short, fine, pointed microtrichia and mechanoreceptors with longer trichoid sensilla mainly on the coxae. In males, the hind femur is strongly modified and swollen and the hind tibia is extremely reduced (Figure 12a, b). The hind femur is characterised also by a prominent ventral protuberance on the basal third with a ventral incision on the apical third having long and stout trichoid and chaetic sensilla in the form of a comb, posteroventrals pointed and grooved (Figure 12c–g). On the basal inner side of the femora, a single campaniform sensillum of about 5.5–6.5 μm in diameter can be found (Figure 12h). The sensillum is characterised by a protuberant inner part with a small but visible pore (Figure 12i, j). The hind basitarsus is extremely elongate, having larger numbers of grooved chaetic sensilla (Figure 12k, l).The tarsomeres have large chaetic sensilla, while distal parts bear more trichoid sensilla (Figure 12m, n). The claws are long, curved, with proximal halves covered by pointed microtrichia and distal halves curved and ribbed, ventral side of the pulvilli with regularly arranged tenent setae with flat capitate terminal plates (Figure 12o–r).

3.2.4. Male and female terminalia

Female terminal segments with microtrichia, ventral sides and the cerci characterised by longer chaetic sensilla (Figure 13a–f), most of the terminal tergites appear to have fewer microtrichia as they are partially retracted into the proximal segment (Figure 13b). The seventh and eight segments of the abdomen have a fine appearance with longer chaetic sensilla mostly apparent along the dorsal portion (Figure 13c–e); chaetic sensilla thickest on tips of cerci (Figure 13f). The terminal part of the male abdomen is covered by dense, very long, rigid and pointed chaetic sensilla (Figure 13g–k). The cercus and epandrium have numerous microtrichia, and trichoid and long chaetic sensilla (Figure 13i, k). The basal part of the phallus is smooth, broad, enlarged, and covered by waxy secretions, and the apex is swollen, bulb-shaped (Figure 13j–l).

3.3. Remarks

Among the known Indian species belonging to the genus Rhamphomyia, the new species appears distinct with its highly modified male hind legs. In addition to the distinct morphological differences between the new species and another recently discovered Indian species (Rhamphomyia bhagati Barták, Akbar, Kanturski, Wachkoo & Maqbool, 2021), there is also a difference in the male internal reproductive tract. The testis is more or less rounded with a basal neck leading into the vas deferens in R. bhagati, compared with an oval testis leading into the vas deferens without having a distinct neck in the new species. Although the male hind leg does appear to be modified very similarly to the R. basalis group, the male terminalia, especially the cercus shape and absence of a subepandrial lobe, do not match the basalis group. The cercus is more similar to those of the pusilla group (sensu Saigusa; see also Sinclair et al. (2019)). Moreover, the females of the new species are without pennate setae on the legs and without infuscated wings, both characteristic features of the basalis group (Sinclair & Saigusa 2018). From the members of the pusilla group, the new species differs in not having darkened halteres, midlegs without modified tibiae and tarsomere and phallus not long and very fine. Rhamphomyia merzi Bartak, 2000 from Kazakhstan, a species similar to the basalis group on the basis of male terminalia, also has the hind femora deformed, but asymmetrical; only the right femur is strongly swollen while the left hind femur is only slightly swollen (Barták 2000), and also not to the extent reported here.

Male hind leg articulation mechanism and involved components (Figure 14). We present here perhaps the first finding of extremely modified male hind legs in Empidinae; the only remotely similar finding comes from Daugeron et al. (2010) regarding the occurrence of highly modified hind legs in Empis subgenus Enoplempis (see Sinclair et al. 2013). Modified hind femora occur in males of some species, e.g. R. merzi. The modified basal part of the tibia is a common feature among the basalis group and many others. A highly thickened or elongated basitarsus of the hind leg is also often reported in the genus. However, a distinctly modified and shortened hind tibia, as reported here, has never been reported previously. The hind basitarsus which is greatly elongated in fact takes over a function of the normal tibia, which is of peculiar occurrence.

Figure 14. Male hind leg articulation mechanism and involved components. (a–d) Locked femorotibial joint and locking apparatus: (a) darkfield micro image of locked femorotibial joint with labelled tibial flexor sclerite (TFS), genuflexor apodeme (GFS) and Heitler’s lump (HL); (c) bright-field micro image of same structure; (b) bright-field micro image of locking apparatus, lateral view with labelled tibial extensor muscles and Heitler’s lump, and flexor sclerite separated from Heitler’s lump; (d) bright-field micro image of same structure. (e–f) locking apparatus in ventro- and dorso-lateral views; (g–j) femorotibial joint in flexed position (g, i) with tibial flexor sclerite (TFS) and Heitler’s lump in physical contact, and in straight position (h, j) with tibial flexor sclerite (TFS) and Heitler’s lump separated.

The enlarged tibial flexor apodeme, presence of robust teeth on the ventral surface, and thickened femur having an enlarged tibial flexor muscle mass, indicates its usage in grasping/holding; this is confirmed by our behavioural observations in the field. The dark-field microphotographs of the femorotibial joint in the male hind leg also reveal a unique locking mechanism. It allows the leg to remain in a flexed position for an extended period of time; this is perhaps an efficient energy-saving feature useful during mating and for prolonged holding of the female. The occurrence of similar structural features and their diverse implicational usage in insect legs are detailed by Földvári et al. (2019). Of the three stated universal locking mechanisms in insect legs, the flexor sclerite lump-engaging mechanism (Type 1) explains best the femorotibial joint articulation of the new species. The locking apparatus consists of an enlarged tibial flexor muscle, relatively reduced tibial extensor muscles, tibial flexor sclerite (TFS), genuflexor apodeme (GFS) and Heitler’s lump (HL) (Figure 14a–f). The lock is present between the tibial flexor sclerite and Heitler’s lump. In the locked state (Figure 14g), the convex transparent ventral surface of the tibial flexor sclerite remains in physical contact with Heitler’s lump (Figure 14i); thereafter the leg can only be opened after forcing the tibial flexor sclerite over and in front of Heitler’s lump (Figure 14h–j). Our laboratory observations and the field observations lead us to postulate that the apparent male hind leg deformation is a secondary sexual character employed to exhibit territoriality and for attracting females. We have also observed the presence of a single campaniform sensillum on the proximal part of the hind leg femur, the presence of which is also supportive of enhanced muscle synergies in substrate grip, similar to that discussed in other studies (Zill et al. 2017).

3.4. Courtship rituals (Figure 15)

The courtship behaviour of the new species illustrated here in brief is somewhat similar to that discussed for a recently described sympatric species in Barták et al. (2021). However, capturing photographic evidence of dance fly behaviour is challenging, as these are fast-moving insects and difficult to focus on, and the interpretation of intriguing aerial images is at times quite difficult. As in the new species of Barták et al. (2021), and some of the other previously reported species (Downes 1970), males raid and prey on small insects and form aerial swarms to display their catch to nearby females in “aerial holding flights”. Such mating swarms often use visual environmental markers and always appear at those certain stationary positions. Once the female accepts the gift and commits to mating, the tangled couple moves at a slower pace and drops down towards the nearby vegetation, where they remain until copulation is completed.

Figure 15. Courtship rituals of Rhamphomyia aquila sp. nov. (a–h) male aerial flight postures displaying territoriality; (i–k) copula with male hind leg usage to detain wilting female; (l) male with prey; (m) male and female in courtship.

Descriptive analysis of observed courtship characters (such as lek height, copulation duration, etc.) mainly depend on the environment and are more or less the same as stated in Barták et al. (2021). Some significant differences do occur among the two species, however. The new species exhibits prey polymorphism, preying on a number of insect species such as psyllids, small flies, etc. Prey polymorphism was not reported in R. bhagati, which preyed only on a specific chironomid species. In both species chironomids are mostly preferred, but the new species preys on relatively larger chironomid species compared with R. bhagati which preyed on a smaller and different chironomid species. The new species is more frequent in occurrence compared with the other species, exhibits strong territoriality and often displays offensive aerial postures (Figure 15a–c). The modified hind legs are displayed and used as specialised structures for holding females in male bias mating swarms (Figure 15d–e). At places with similar lekking sites, the males of the two species are observed to encounter each other. The males of the new species chase off males of the other species during such encounters and retain the area (Figures 15f–h). The distinct trait morphology of the new species is certainly associated with mating success and prolonged copula duration (Figure 15i–m). We are currently quantifying more precisely the role of legs as specialised structures in aerial display signalling, and their selective advantage. The deformed legs have given a selective advantage to the species and have favoured their predominance in the region.

4. Discussion

Males have a much larger potential benefit from engaging in copulation (Parker 1979). Selection pressure leads males towards mating, while females shy away. This pressure on occasion leads to the development of male-specific morphological characters for coercing unwilling females to mate (Bergsten 2005). We observed that the deformed male hind legs are used to take hold of the female abdomen for a proper genital union and to detain an initially wilting female until the ejaculate is transferred (Figure 15i–m). In future research we will generate predictions based on these functions and test whether these predictions are consistent with observations. Among possible male phenotypes the degree of leg deformation should covary with the duration of copulation and vice versa. Our discovery adds to the list of already apparently deceptive traits in empidid flies and suggests them as a potential model to evaluate inconclusive empirical evidence about sexual selection and secondary sexual traits as drivers for speciation.

The external as well as the internal genital tract in Diptera is generally poorly known, with only a few detailed comparative studies available (Sinclair et al. 2007; Puniamoorthy et al. 2010). The same is true in the family Empididae, where apart from Smith (1969) nothing much can be cited. In addition to the external male and female genital tract we herewith have detailed the internal genital system, which perhaps represents the first such detail for the genus as well. Previously works of Loew (1841), Dufour (1851), Keuchenius (1913) and Smith (1969) are rather brief without labels or proper descriptions. The spermatheca is here illustrated in greater detail for the family Empididae for the first time, although it was previously reported and illustrated for other insect orders and various families within the order Diptera (Pascini & Martins 2017). Whether the structure in this species aids post-copulatory sperm competition remains a fascinating topic to be explored. Not only do the details of the internal reproductive tract have taxonomic significance, but its functional advantages vary among species. It is postulated that the length of the sperm duct between the sperm pump and opening roughly corresponds to the length of the male phallus (Barták, unpublished data). By clasping copulating pairs quickly by hand, and subsequently dissecting them, it can be observed that the whole length of the phallus, even if it is very long (as in Rhamphomyia (Holoclera) nigripennis group), is inserted into the female.

5. Checklist of Indian Empididae

An updated checklist of the family Empididae (Diptera) of India is presented. It includes 55 species belonging to 13 genera. The checklist is primarily based on the available literature with all the names of described species being presented in accordance with the most recent classification. Notes about type localities, depositories, and relevant references to each species record are given. The list provides a synthesis of the regional taxonomical work carried out to date and will serve as a baseline for future studies. Within the Indian Empididae, the genus Chelifera is the most species rich, represented by 10 species, followed by Clinocera (nine), Empis (eight), Hemerodromia (six) and Rhamphomyia (four). The genera Heleodromia, Hilara, and Roederiodes are each represented by three species, while Trichoclinocera and Chelipoda are each represented by two species and the genera Trichopeza and Wiedemannia are each represented by a single species. For the genus Rhamphomyia we had previously stated the presence of four species – R. bhagati Barták, Akbar, Kanturski, Wachkoo and Maqbool, 2021, R. griseonigra Brunetti, 1913, R. himalayana Brunetti, 1913 and R. unifasciata Brunetti, 1913 – from the region (Barták et al. 2021). However, R. unifasciata is now treated as Ocydromia unifasciata (Brunetti, 1913), a member of Hybotidae, and is therefore excluded from the list. As such, the genus in India is represented by three previously described species only. The new species described here represents the fourth species belonging to the genus Rhamphomyia to be reported from India. The classification of Empidoidea suggested by Wahlberg and Johanson (2018) is followed here. According to their study, the family Empididae globally comprises 3200 known species, and more than 80 genera, in three subfamilies (Brachystomatinae, Clinocerinae and Empidinae).

Family Empididae Latreille, 1804

Subfamily Brachystomatinae Melander, 1908

Tribe Trichopezini Vaillant, 1981

Genus Heleodromia Haliday, 1833

Heleodromia baculifera Tokarczyk and Kovalev, 1986

Heleodromia baculifera Tokarczyk and Kovalev, 1986: 56. Holotype ♂, Lahaul, Pancha [Panch] Nala Valley Himachal Pradesh, India [PAN].

Distribution

India (Himachal Pradesh) (Tokarczyk & Kovalev 1986: 58; Yang et al. 2007: 451).

Heleodromia obscura (Brunetti, 1913)

Clinocera obscura Brunetti, 1913: 34. Syntypes 2 ♂♂, Shimla [Simla], Himachal Pradesh, India [ZSI].

Distribution

India (Himachal Pradesh) (Brunetti 1913: 34, 1917: 80, 1920: 366; Yang et al. 2007: 452).

Heleodromia rami Wagner and Leese, 2004

Heleodromia rami Wagner and Leese in Wagner et al. 2004: 15. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 15; Yang et al. 2007: 452).

Genus Trichopeza Róndani, 1856

Trichopeza fusca Brunetti, 1913

Trichopeza fusca Brunetti, 1913: 31. Holotype ♀, Kurseong, Darjeeling [Darjiling], West Bengal, India [ZSI].

Distribution

India (West Bengal) (Brunetti 1913: 32, 1920: 373; Yang et al. 2007: 457).

Subfamily Clinocerinae Collin, 1928

Genus Clinocera Meigen, 1803

Clinocera cuspidata Wagner and Leese, 2004

Clinocera cuspidata Wagner and Leese in Wagner et al. 2004: 16. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 16; Yang et al. 2007: 55).

Clinocera longicercus Wagner and Leese, 2004

Clinocera longicercus Wagner and Leese in Wagner et al. 2004: 16. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 16; Yang et al. 2007: 56).

Clinocera lunata Wagner and Leese, 2004

Clinocera lunata Wagner and Leese in Wagner et al. 2004: 18. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 18; Yang et al. 2007: 56).

Clinocera lunatoides Wagner and Leese, 2004

Clinocera lunatoides Wagner and Leese in Wagner et al. 2004: 18. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 18; Yang et al. 2007: 56).

Clinocera marginesetosa Wagner and Leese, 2004

Clinocera marginesetosa Wagner and Leese in Wagner et al. 2004: 16. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 18; Yang et al. 2007: 56).

Clinocera minutissima (Vaillant, 1960)

Atalanta minutissima Vaillant, 1960: 172. Lectotype ♂, Khorogon Gunt River, Tajikistan [MZLS].

Distribution

India (Himachal Pradesh), Tajikistan (Vaillant 1960: 172; Wagner et al. 2004: 17; Yang et al. 2007: 56; Sinclair & Shamshev 2020: 267).

Clinocera setosa Wagner and Leese, 2004

Clinocera setose Wagner and Leese in Wagner et al. 2004: 18. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 18; Yang et al. 2007: 57).

Clinocera sinclairi Wagner and Leese, 2004

Clinocera sinclairi Wagner and Leese in Wagner et al. 2004: 19. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 19; Yang et al. 2007: 57).

Clinocera stackelbergi (Vaillant, 1960)

Atalanta stackelbergi Vaillant, 1960: 174. Lectotype ♂, Khorogon Gunt River, Tajikistan [ZIN].

Distribution. India (Himachal Pradesh), Tajikistan (Vaillant 1960: 174; Wagner et al. 2004: 18; Yang et al. 2007: 58; Sinclair & Shamshev 2020: 268).

Genus Dolichocephala Macquart, 1823

Dolichocephala flamingo Smith, 1965

Dolichocephala flamingo Smith, 1965: 98. Holotype ♂, Tumlingtar, Arun Valley, Nepal [NHMUK].

Dolichocephala tibetensis Liu, Tang and Yang, 2014: 1023. Holotype ♂, Bomi, Galonglashan, Tibet [CAU].

Distribution

China, India (Himachal Pradesh), Nepal (Smith 1965: 99; Wagner et al. 2004: 22; Yang et al. 2007: 60; Liu et al. 2014: 1024; Sinclair 2017: 291).

Dolichocephala panesari Wagner and Leese, 2004

Dolichocephala panesari Wagner and Leese inWagner et al. 2004: 20. Holotype ♂, Nishala [Nishalla] Nalla, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 20; Yang et al. 2007: 62).

Dolichocephala rotundinota Wagner and Leese, 2004

Dolichocephala rotundinota Wagner and Leese in Wagner et al. 2004: 20. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 20; Yang et al. 2007: 62).

Dolichocephala septemnotata Brunetti, 1913

Dolichocephala septemnotata Brunetti, 1913: 35. Holotype ♂, Shimla [Simla], Himachal Pradesh, India [ZSI].

Distribution

India (Himachal Pradesh) (Brunetti 1913: 36, 1917: 81, 1920: 371; Yang et al. 2007: 62).

Genus Roederiodes Coquillett, 1901

Roederiodes bilobatus Wagner and Leese, 2004

Roederiodes bilobatus Wagner and Leese in Wagner et al. 2004: 22. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 22; Yang et al. 2007: 69).

Roederiodes naggarense Wagner and Leese, 2004

Roederiodes naggarense Wagner and Leese in Wagner et al. 2004: 22. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 22; Yang et al. 2007: 70).

Roederiodes schwoerbeli Wagner and Leese, 2004

Roederiodes schwoerbeli Wagner and Leese in Wagner et al. 2004: 22. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 22; Yang et al. 2007: 70).

Genus Trichoclinocera Collin, 1941

Trichoclinocera fluviatilis (Brunetti, 1913)

Clinocera fluviatilis Brunetti, 1913: 34. Holotype ♂, Bhowali, Uttarakhand, India [ZSI].

Distribution

India (Himachal Pradesh, Uttarakhand) (Brunetti 1913: 35, 1920: 366; Sinclair 1994: 1016; Wagner et al. 2004: 25; Sinclair & Saigusa 2005: 199; Yang et al. 2007: 71).

Trichoclinocera serrata Wagner and Leese, 2004

Trichoclinocera serrata Wagner and Leese in Wagner et al. 2004: 25. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 25; Yang et al. 2007: 72).

Genus Wiedemannia Zetterstedt, 1838

Wiedemannia glaucescens (Brunetti, 1917)

Clinocera glaucescens Brunetti, 1917: 80. Syntypes 2 ♀♀, Phagu, Himachal Pradesh, India [ZSI].

Acanthoclinocera saigusai Smith, 1965: 102. Holotype ♂, Dobhan, Taplejung, Nepal [NHMUK].

Wiedemannia tibetensis Wang, Wang and Yang, 2015: 45. Holotype ♂, Nyingchi, Sejilashan, Tibet [CAU].

Distribution

China, India (Himachal Pradesh), Nepal (Brunetti 1917: 81; Smith 1965: 103; Wagner et al. 2004: 17; Yang et al. 2007: 77; Wang et al. 2015: 46; Sinclair 2017: 291).

Subfamily Empidinae Latreille, 1809

Tribe Chelipodini Hendel, 1936

Genus Chelipoda Macquart, 1823

Chelipoda flavida Brunetti, 1913

Chelipoda flavida Brunetti, 1913: 32. Syntypes ♂, ♀, Chota Nagpur, Jharkhand; Darjeeling [Darjiling], Paresnath, West Bengal, India; Dawna Hills, Myanmar [ZSI].

Distribution

India (Jharkhand, West Bengal), Myanmar, Thailand (Brunetti 1913: 33, 1920: 369; Plant 2009: 257; Yang et al. 2007: 252).

Chelipoda indica (Brunetti, 1913)

Litanomyia indica Brunetti, 1913: 36. Holotype ♀, Darjeeling [Darjiling], West Bengal, India [ZSI].

Distribution

India (West Bengal) (Brunetti 1913: 36, 1920: 370; Yang et al. 2007: 253).

Tribe Empidini Collin 1961

Genus Empis Linnaeus, 1758

Empis amplitarsis Brunetti, 1920

Empis amplitarsis Brunetti, 1920: 349. Holotype ♂, Belgaum, Karnataka, India [NHMUK].

Distribution

India (Karnataka) (Brunetti 1920: 350; Yang et al. 2007: 130).

Empis centralis Brunetti, 1913

Empis centralis Brunetti, 1913: 26. Holotype ♀, Mundali, Uttar Pradesh, India [ZSI].

Distribution. India (Uttar Pradesh) (Brunetti 1913: 27, 1920: 354; Yang et al. 2007: 132).

Empis elegans Brunetti, 1913

Empis elegans Brunetti, 1913: 26. Syntypes 2 ♀♀, Mundali, Uttar Pradesh, India [ZSI].

Distribution

India (Uttar Pradesh) (Brunetti 1913: 26, 1920: 357; Yang et al. 2007: 133).

Empis griseonigra Brunetti, 1913

Empis griseonigra Brunetti, 1913: 25. Holotype ♂, Mundali, Uttar Pradesh, India [ZSI].

Distribution

India (Uttar Pradesh) (Brunetti 1913: 26, 1920: 353; Yang et al. 2007: 134).

Empis inconspicua Brunetti, 1913

Empis inconspicua Brunetti, 1913: 28. Syntypes 2 ♂♂, Lucknow, Uttar Pradesh, India [ZSI].

Distribution

India (Uttar Pradesh) (Brunetti 1913: 28, 1920: 357; Yang et al. 2007: 135).

Empis marginata Brunetti, 1917

Pachymeria marginata Brunetti, 1917: 79. Holotype ♀, Between Kufri and Phagu, Himachal Pradesh, India [ZSI].

Distribution

India (Himachal Pradesh) (Brunetti 1917: 80, 1920: 356; Yang et al. 2007: 136).

Empis rostrata Brunetti, 1913

Empis rostrata Brunetti, 1913: 25. Holotype ♀, Theog, Shimla [Simla], Himachal Pradesh, India [ZSI].

Distribution

India (Himachal Pradesh) (Brunetti 1913: 25, 1917: 79, 1920: 356; Yang et al. 2007: 140).

Empis subcilipes Brunetti, 1913

Empis subcilipes Brunetti, 1913: 24. Holotype ♀, Mundali, Uttar Pradesh, India [ZSI].

Distribution

India (Uttar Pradesh) (Brunetti 1913: 25, 1920: 355; Yang et al. 2007: 141).

Genus Rhamphomyia Meigen, 1822

Rhamphomyia bhagati Barták, Akbar, Kanturski, Wachkoo and Maqbool, 2021

Rhamphomyia (Pararhamphomyia) bhagati Barták, Akbar, Kanturski, Wachkoo and Maqbool, 2021: 70. Holotype ♂, Central Institute of Temperate Horticulture, Srinagar, Jammu and Kashmir [CITH].

Distribution

India (Jammu and Kashmir) (Barták et al. 2021: 72).

Rhamphomyia griseonigra Brunetti, 1913

Rhamphomyia griseonigra Brunetti, 1913: 29. Holotype ♂, Mundali, Uttar Pradesh, India [ZSI].

Distribution

India (Uttar Pradesh) (Brunetti 1913: 30, 1920: 353; Yang et al. 2007: 183).

Rhamphomyia himalayana Brunetti, 1913

Rhamphomyia himalayana Brunetti, 1913: 28. Holotype ♀, Matiana, Himachal Pradesh, India [ZSI].

Distribution

India (Himachal Pradesh) (Brunetti 1913: 29, 1917: 80, 1920: 346; Yang et al. 2007: 183).

Tribe Hemerodromiini Schiner, 1862

Genus Chelifera Macquart, 1823

Chelifera accomodata Wagner and Leese, 2004

Chelifera accomodata Wagner and Leese in Wagner et al. 2004: 10. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 10; Yang et al. 2007: 259).

Chelifera brevidigitata Wagner and Leese, 2004

Chelifera brevidigitata Wagner and Leese in Wagner et al. 2004: 10. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 10; Yang et al. 2007: 259).

Chelifera curvata Wagner and Leese, 2004

Chelifera curvata Wagner and Leese in Wagner et al. 2004: 7. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 7; Yang et al. 2007: 260).

Chelifera digitata Wagner and Leese, 2004

Chelifera digitata Wagner and Leese in Wagner et al. 2004: 10. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 10; Yang et al. 2007: 260).

Chelifera haeselbarthae Wagner and Leese, 2004

Chelifera haeselbarthae Wagner and Leese in Wagner et al. 2004: 11. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 10; Yang et al. 2007: 261).

Chelifera insueta Wagner and Leese, 2004

Chelifera insueta Wagner and Leese in Wagner et al. 2004: 5. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 5; Yang et al. 2007: 261).

Chelifera multiseta Wagner and Leese, 2004

Chelifera multiseta Wagner and Leese in Wagner et al. 2004: 6. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 6; Yang et al. 2007: 261).

Chelifera multisetoides Wagner and Leese, 2004

Chelifera multisetoides Wagner and Leese in Wagner et al. 2004: 7. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 7; Yang et al. 2007: 261).

Chelifera rhombicercus Wagner and Leese, 2004

Chelifera rhombicercus Wagner and Leese in Wagner et al. 2004: 7. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 7; Yang et al. 2007: 263).

Chelifera stauderae Wagner and Leese, 2004

Chelifera stauderae Wagner and Leese in Wagner et al. 2004: 8. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 8; Yang et al. 2007: 263).

Genus Hemerodromia Meigen, 1822

Hemerodromia acutata Grootaert, Yang and Saigusa, 2000

Hemerodromia acutata Grootaert, Yang and Saigusa, 2000: 73. Holotype ♂, Menglun, Xishuangbanna, China [Holotype, ♂ CAU].

Distribution

China, India (Himachal Pradesh), Thailand (Grootaert et al. 2000: 75; Wagner et al. 2004: 11; Plant 2015: 7; Yang et al. 2007: 267).

Hemerodromia chitaoides Wagner and Leese, 2004

Hemerodromia chitaoides Wagner and Leese in Wagner et al. 2004: 13. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 13; Yang et al. 2007: 268).

Hemerodromia dorsalis (Brunetti, 1913)

Chelipoda dorsalis Brunetti, 1913: 33. Syntypes ♂, ♀, Barog [Barogh], Himachal Pradesh, India [ZSI].

Distribution

India (Himachal Pradesh) (Brunetti 1913: 34, 1917: 81, 1920: 367; Yang et al. 2007: 269).

Hemerodromia elongatiodes Wagner and Leese, 2004

Hemerodromia elongatiodes Wagner and Leese in Wagner et al. 2004: 13. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 13; Yang et al. 2007: 269).

Hemerodromia rhomboides Wagner and Leese, 2004

Hemerodromia rhomboides Wagner and Leese in Wagner et al. 2004: 13. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 13; Yang et al. 2007: 273).

Hemerodromia subspinosa Yang, Zhang and Zhang, 2007

Hemerodromia spinosa Wagner and Leese, 2004: 13. Holotype ♂, Kullu Valley, Himachal Pradesh, India [ZFMK].

Distribution

India (Himachal Pradesh) (Wagner et al. 2004: 13; Yang et al. 2007: 274).

Tribe Hilarini Collin 1961

Genus Hilara Meigen, 1822

Hilara bares Walker, 1849

Hilara bares Walker, 1849: 491. Holotype ♂, India [East India] [NHMUK].

Distribution

India (Walker 1849: 491; Brunetti 1920: 359; Yang et al. 2007: 211).

Hilara compacta Brunetti, 1913

Hilara compacta Brunetti, 1913: 30. Syntypes, 3 ♂♂, Shimla [Simla], Himachal Pradesh, India [ZSI].

Distribution

India (Himachal Pradesh) (Brunetti 1913: 31, 1917: 80, 1920: 359; Yang et al. 2007: 214).

Hilara rufithorax (Brunetti, 1913)

Empimorpha rufithorax Brunetti, 1913: 30. Holotype ♂, Darjeeling [Darjiling], West Bengal, India [ZSI].

Distribution

India (West Bengal) (Brunetti 1913: 30, 1920: 360; Yang et al. 2007: 232).

Acknowledgements

The first author thanks the Department of Science and Technology (DST), Govt. of India, New Delhi, for research encouragement and financial assistance rendered via the N-PDF Fellowship programme, File No: PDF/2015/000866. The authors also thank Darryl Gwynne (University of Toronto, Mississauga, Canada) and Luc Bussière (Biological and Environmental Sciences, University of Stirling, United Kingdom) for their valuable suggestions. We are highly thankful to Adrian Plant (Mahasarakham University, Thailand) and Paul Beuk (Natuurhistorisch Museum Maastricht) for their help with the literature. We also thank the reviewers for immensely improving the manuscript. Sincere thanks are due to the director of CITH for making facilities available.

Disclosure statement

No potential conflict of interest was reported by the authos.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/24750263.2022.2139864

Additional information

Funding

This work was supported by the Department of Science and Technology (DST), Govt. of India, New Delhi, via the N-PDF Fellowship programme [PDF/2015/000866].