Empis (Enoplempis) nuda Loew

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 : 431-433

Empis (Enoplempis) nuda Loew

( Figs 12 D, E, 15A, 18A)

Empis nuda Loew, 1862: 195 . Type locality: Illinois, USA.

Type material examined. HOLOTYPE, ♂ labelled: “ Type / 1104 [red label with white top border]”; “Illinois/ Barron. [green label]”; “Loew”; “ nuda / m”; “ HOLOTYPE / Empis ♂/ nuda / Loew/ teste WJ Turner [re label]” [dissected; hindlegs mounted on card] (MCZ).

Additional material examined. CANADA. Ontario: Essex Co., Point Pelee NP, Visitor’s Centre, MT, 29.v.- 9.vi.2000, O. Lonsdale (1 ♂, DEBU); Leamington, Point Pelee NP, 14.vi.1984, B.V. Brown (3♂, DEBU); Simcoe, 2.vi.1939, G.E. Shewell (3 ♂, CNC); Wellington Co., Arkell, damp cedar stand, 31.v.2002, O. Lonsdale (2 ♀, DEBU). USA. Illinois: Chicago, 9.v.1896, W.M. Wheeler (1 ♂, 1 ♀, AMNH). New Jersey: Baleville, 28.v.1935, C.H. Curran (3 ♂, AMNH); Branchville, 13.v.1931, C.H. Curran (2 ♂, AMNH); Greenwood Lake, 19.v.1918, F.M. Schott (1 ♂, USNM). New York: Cooks Falls, 5.vi.1930, S.W. Bromley (1 ♂, USNM); Ithaca, 15.v.1915, 14.v.1916 (3 ♂, CUIC, USNM); Ithaca, 23.v.1936, H.K. Townes (1 ♂, USNM). Pennsylvania: Centre Co., Spring Ck, 550 ft., 2 mi S Bellefonte, 21.v.2005, J.B. Runyon (1 ♂, MTEC); Dauphin Co., Grantville, 24.v.1962, J.R. Vockeroth (2 ♂, CNC); Spring Branch, 23.v.1945, DDT Expt. (1 ♂, USNM).

Diagnosis. This species is distinguished by the setae of hind trochanter confined to distinct tubular process, paint brush-like; hind tibia with rows of long slender dorsal setae, longer than width of tibia; hypandrium 0.5× length of epandrium, apex tapered and rounded; setae present on membrane anterior to base of hypandrium.

Re-description. Wing length 6.2–7.6 mm. Male. Head dark in ground-colour, with dense greyish pruinescence on face, frons, postgena and occiput. Dichoptic, eye with ommatidia of equal size. Frons divergent towards antennae; below ocellar triangle slightly wider than width of anterior ocellus, bearing short setulae along inner margin of eye. 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 0.5× 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, long and stout. 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 more than 4× longer than basal width, 3× longer than stylus. Palpus yellow, with setulae dark. Proboscis largely yellowish; apex of labrum reddish brown; labellum with dark setae.

Thorax dark in ground-colour, largely densely grey pruinescent: postpronotum, supra-alar ridge and lower margin of scutellum yellowish orange. Scutum with pair of distinct dark vittae between acr and dc rows; distinct pair of vittae lateral to dc and above notopleural depression. Pleura entirely grey, lacking paler highlights. Proepisternum greyish, with several short dark setae; prosternum bare. Antepronotum with row of short, stout dark setae. Postpronotum with 1–2 long, dark setae and 3–6 shorter setae. Scutum with sparse row of fine acr setulae; dc longer than acr, increasing in length posteriorly; 1–2 posterior npl, 1 anterior npl and several shorter dark setae; 1 short presut spal; 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 2–4 long dark setae. Anterior and posterior spiracles pale.

Legs long, entirely yellow, except for dark ring at trochanter-femur junction and apices of femora; tarsi becoming darker apically. Coxae with numerous dark lateral setae, longer and stouter along apical anterior margins. Hind trochanter with setae confined to distinct tubular process, paint brush-like; usually setae tightly appressed and tapered to pointed apex ( Fig. 12 D). Femora lacking posteroventral row of fine setae; hind femur with anteroventral row of short, slender setae with dark, stout seta on apical 0.25; hind femur long and cylindrical, somewhat swollen subapically ( Fig. 12 E), with several preapical anterior setae. Fore tibia clothed in long dark setae, shorter than width of tibia; with 2–3 dorsal, 3–4 posterodorsal, 4–5 posterior, 3–4 posteroventral and several preapical setae. Mid tibia clothed in long dark setae, shorter than width of tibia; 2 anteroventral, 3–4 anterodorsal, 3 anterior, 3–4 posterodorsal, 4 posterior, 1–2 posteroventral and several preapical setae. Hind tibia with 5 antero- and posterodorsal setae, several posterior, posteroventral and preapical setae, mostly distinctly longer than width of tibia ( Fig. 12 E). Tarsomeres 1–5 of all legs with rows of antero- and posteroventral spine-like setae; fore tarsomere 1 somewhat swollen, similar in size to hind tarsomere 1, with 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.

Abdomen concolorous with pleura, paler along apical margin; marginal setae long and stout on tergites 1–7. Marginal setae on tergite 8 longer than length of sclerite. Pregenital segments unmodified; sclerites of segment 8 weakly separated, not weakly sclerotized dorsally. Terminalia ( Fig. 15 A) largely yellow, except dorsal margin of cerci dark. Cercus narrow, appressed to dorsal margin of epandrium, linear, broader at anterior end; dorsal margin with broad preapical, tooth-like projection. Hypoproct with upper half clothed with many long setae. Epandrial lamella subtriangular, posterior margin curving dorsally, bearing short apical setae. Hypandrium prolonged posteriorly with rounded margin, about 0.5× as long as epandrium; base with several short, dark setae on membrane anterior to base, more than 0.5× length of hypandrium. Phallus with broad base, with deep attenuation near base; sharply bent on apical half; apex just emerging beyond cercus; apex of phallus broadly expanded, scooplike; ejaculatory apodeme 0.75× length of epandrium; inverted Y-shaped, with median keel reduced.

Female. Similar to male, except as follows: frons slightly broader; hind trochanter lacking paint brush-like process; cercus long and slender, slightly shorter than tergite 8.

Geographical distribution and seasonal occurrence ( Fig. 18 A). Empis (En.) nuda is known from southern Ontario and the northeastern USA (Illinois, New York, Pennsylvania and New Jersey). Adults have been collected from early May to mid-June.

Nuptial gift presentation. Form unknown.

Figures

FIGURE 12. Male legs of E. (Enoplempis). A, E. montywoodi, apex of hind femur and base of hind tibia, anterior view; B, E. montywoodi, apex of hind femur and base of hind tibia, posterior view; C, E. nodipoplitea, apex of hind femur and base of hind tibia, anterior view; D, E. nuda, hind trochanters; E, E. nuda, hindleg, anterior view.

FIGURE 15. Male terminalia, lateral view of E. (Enoplempis). A, E. nuda; B, E. pectinata.

FIGURE 18. Distribution of E. (Enoplempis). A, E. nuda and E. prodigiosa; B, E. enodis, E. montywoodi, E. pectinata, and E. penicillata.