Empis (Enoplempis) vockerothi Cumming

Sinclair, Bradley J., Brooks, Scott E. & Cumming, Jeffrey M., 2013, Revision of the Empis subgenus Enoplempis Bigot, east of the Rocky Mountains (Diptera: Empididae), Zootaxa 3736 (5), pp. 401-456 : 448-449

Empis (Enoplempis) vockerothi Cumming sp. nov.

( Figs 1 A, B, C, E, 14B, 19E, 21B)

Type material. HOLOTYPE, ♂ labelled: “Niagara Glen,/ Ont., 22.V.66 / J.R. Vockeroth”; “Bearing/ balloons”; “ HOLOTYPE / Empis (Enoplempis) / vockerothi / Cumming [red label]” (CNC). PARATYPES: CANADA. Ontario: Dundas, below Borer’s Falls, 43°17'25''N 79°55'60''W, 5.vi.2011, 10.vi.2012, B.J. Sinclair (1 ♂, 7 ♀, CNC); Niagara Glen, 1.vi.1926, G.S. Walley (4 ♂, CNC); Niagara Glen, 29.v.1956, 43°8'N 79°3'W, J.R. Vockeroth (5 ♀, CNC); Niagara Glen, 22.v.1966, bearing balloons, J.R. Vockeroth (7 ♂, CNC). USA. New York: Tompkins Co., McLean Bogs Nat. Area Res., 20–27.v.1999, flight int. trap nr bog, H. Song & J.K. Liebherr (1 ♂, CUIC). Ohio: Hocking Co., Laurel Twp, Crane Hollow St. Nat. Pre., N. rim Brieneinger Hollow, GAC 2797, 11.v.2005, G.A. Coovert (1 ♂, CHIC); same locality, GAC 3155#5, 12.v.2009, G.A. Coovert (2 ♂, CHIC); same locality, GAC 3298#4A,B,C, 7.v.2011, G.A. Coovert [with balloons] (3 ♂, CHIC); same locality, GAC 3298#4D, 7.v.2011, G.A. Coovert [with balloons] (6 ♂, CNC); same locality except, S end of valley, GAC 2794#1, 6.v.2005, G.A. Coovert (1 ♂, CHIC); same locality except, S end of preserve below gas well #8841, GAC 3153#4, 5.v.2009, G.A. Coovert (17 ♂, CHIC); same locality except, Ellis House at blacklight, GAC 3223, 5.v.2010, G.A. Coovert (1 ♂, CHIC). Virginia: Giles Co., Cascades Rec. Area, 37°21'00''N 80°36'30''W, 17.v.2005, S.A. Marshall (1 ♂, DEBU); Mt. Rogers, 4500–5400 ft., 1.vi.1962, J.G. Chillcott (1 ♂, 2 ♀, CNC).

Diagnosis. This small species is distinguished by nearly holoptic males, unmodified setae on hindlegs; apex of epandrium tapered; posterior margin of hypandrium rounded, produced posteriorly; bearing short setae, less than length of hypandrium; cercus greatly narrowed apically.

Description. Wing length 4.0–5.0 mm. Male. Head dark in ground-colour, with dense greyish pruinescence on face, frons, postgena and occiput. Very narrowly dichoptic, eye with ommatidia of equal size; short setulae along separation of eyes; frons triangular above antennae. Face slightly divergent towards mouthparts; bare with oral margin shining. Ocellar triangle dark, subshining, with pair of parallel ocellar setae and pair of posterior setulae one-third length of ocellar setae. Occiput bearing row of postocular setae, stout and black on upper section; shorter and more slender on lower section; occipital setae black, longer and stouter than postocular setae. Postpedicel, stylus and scape mostly dark; somewhat paler at inner base of postpedicel and inner apex of pedicel. Scape about 2× longer than pedicel; postpedicel about 4× longer than basal width, 2.5× longer than stylus. Palpus yellow, with setulae dark. Proboscis largely yellowish brown; apex of labrum reddish brown; labellum with dark setae.

Thorax dark in ground-colour, largely densely grey pruinescent: postpronotum and supra-alar ridge yellowish orange. Scutum grey pruinose without vittae. Pleura grey, with faint yellowish margins of some sclerites. Proepisternum greyish, with several short, dark setae; prosternum bare with area between coxae yellowish. Antepronotum with row of short setulae. Postpronotum with 1 long, dark setae and 3–4 shorter setae. Scutum lacking acr; 8–10 dc short and slender, 0.5× length of middle npl, increasing in length somewhat posteriorly; 3 npl and 1–2 shorter dark setae, middle npl longest; 1 presut spal, subequal in length to anterior npl; 1 psut spal; 1 pal. Scutellum with 2 pairs of sctl, apical pair subequal in length to pal, outer pair shorter than apical pair. Laterotergite with 3–5 long dark setae. Anterior and posterior spiracles pale.

Legs long, entirely yellow to yellowish brown, except for dark ring at trochanter-femur junction and apices of femora; tibiae and tarsi becoming darker apically. Coxae with numerous dark lateral setae, longer and stouter along apical anterior margins. Hind trochanter lacking modifications. Fore femur lacking ventral rows of fine setae; mid and hind femora with multiple rows of short slender setae; hind femur long and cylindrical, slightly swollen subapically ( Fig. 19 E). Fore tibia clothed in long dark setae, shorter than width of tibia; with 4–5 dorsal, 3–4 posterodorsal and several preapical setae. Mid tibia clothed in long dark setae, shorter than width of tibia with few outstanding setae; 2–3 anterodorsal and several preapical setae. Hind tibia clothed in long dark setae, shorter than width of tibia, with row of numerous posterodorsal setae and several preapical setae; dorsal setae mostly distinctly longer than width of tibia ( Fig. 19 E). Tarsomeres 1–5 of all legs with rows of antero- and posteroventral spine-like setae; fore tarsomere 1 slender, not swollen and lacking long outer setae.

Wing clear with yellowish brown veins; all veins complete (except Sc), well sclerotized. Basal costal seta not distinguished. R5 and M1 divergent near wing margin; R5 ending beyond wing tip; radial fork acute. Halter yellow.

Abdominal tergites dark brown, lacking grey pruinescence, paler along apical and posterior margins; marginal setae long and stout on tergites 1–7; sternites pale brown. Marginal setae on tergite 8 longer than length of sclerite. Pregenital segments unmodified; sclerites of segment 8 closely approximate laterally, weakly sclerotized dorsomedially. Terminalia ( Fig. 21 B) largely yellow, except cerci dark. Cercus separated from dorsal margin of epandrium; quadrate anteriorly, greatly narrowed posteriorly; inner apical margin clothed in dense fine setae; narrow outer lobe with straight stout setae posteriorly. Hypoproct lacking setae; with pair of short slender projections, directed ventromedially. Epandrial lamella elongate, subtriangular; longer than cercus; posterior margin evenly tapered, bearing apical setae. Hypandrium slightly produced posteriorly, with rounded apical margin, about 0.33× as long as epandrium; bearing several short, dark setae, less than length of hypandrium. Phallus broadly tubular, with broadly rounded apex and slender, anterior apical filament; ejaculatory apodeme about 0.5× length of epandrium; flattened.

Female. Similar to male, except as follows: frons more widely separated, subequal to width of anterior ocellus; ventral setae on mid and hind femora shorter and not erect; hind femur with 1 or 2 strong ventral preapical setae; cercus long and slender, subequal in length to tergite 8.

Geographical distribution and seasonal occurrence ( Fig. 14 B). Empis (En.) vockerothi ranges from southwestern Ontario south to Virginia. Adults have been collected from early May to mid-June.

Etymology. This species is named in memory of CNC dipterist, Dr. J. Richard (Dick) Vockeroth, who collected a number of type specimens from Niagara Glenn, Ontario, including several males bearing balloons.

Nuptial gift presentation. Males of E. (En.) vockerothi present empty (prey-less) balloons to females ( Figs 1 A, B). The balloons that are formed are cylindrical with the posterior end deeply concave. Males apparently hold the fully formed balloon primarily with their midlegs, which are crossed around its tapered anterior end. Unlike the related E. (En.) snoddyi , mating swarms of E. (En.) vockerothi found in Crane Hollow, Ohio, are formed by males for one to three hours shortly after midday, under the canopy of hemlock trees ( Tsuga ) approximately 2–5 metres above the ground ( Fig. 1 C) (G.A. Coovert, pers. comm. 2011).

Remarks. Empis (En.) vockerothi appears to be the sister species to E. (En.) snoddyi , where the former ranges from southwestern Ontario to Virginia, and the latter occurs from Virginia south through the Great Smoky Mountains.

Figures

FIGURE 1. Empis (Enoplempis) species. A, B, E. vockerothi (Hocking Co., OH) male with balloon (photographs by Allen Coovert); C, swarming males of E. vockerothi with balloons shown by arrows (photograph by Allen Coovert); D, E. snoddyi (Sevier, TN) apparently in the process of forming a balloon (photograph by Thomas Bentley, copyright Thomasbentley. com); E, E. vockerothi, male; F, E. appalachicola, male; G, E. tridentata, male. Scale bars = 2 mm.

FIGURE 14. Distribution of E. (Enoplempis). A, E. loripedis and E. nodipoplitea; B, E. vockerothi and E. volsella.

FIGURE 19. Male legs of E. (Enoplempis). A, E. snoddyi, hindleg, anterior view; B, E. stenoptera, hindleg, anterior view; C, E. stenoptera, hind trochanter, anterior view; D, E. tridentata, hindleg, anterior view; E, E. vockerothi, hindleg, anterior view.

FIGURE 21. Male terminalia, lateral view of E. (Enoplempis). A, E. tridentata; B, E. vockerothi.