Empis (Enoplempis) ctenocnema Melander

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 : 415-416

Empis (Enoplempis) ctenocnema Melander

( Figs 5 B, 6D, 7B)

Empis (Enoplempis) ctenocnema Melander, 1945: 87 . Type locality: Tuxedo, New York, USA.

Type material examined. LECTOTYPE (here designated in order to fix identity of the species) ♂, labelled: “Tuxedo N.Y./ 29 May ’26/ ALMelander”; “ HOLOTYPE / ctenocnema [red label]”; “ALMelander/ Collection/ 1961”; “d. L. Knutson’6 [left wing, hind legs and abdomen (with genitalia) glued to bottom label]”; “ LECTOTYPE / Empis (Enoplempis) / ctenocnema Melander / des. Sinclair, Brooks &/ Cumming 2013 [red label]” (USNM). PARALECTOYPES: 1 ♂, 1 ♀ same data as lectotype (whereabouts unknown).

Additional material examined. CANADA. Quebec: Montreal, 10.vi.1900,vi.01, C.W. Johnson Coll. (2 ♂, 1 ♀, CNC); Ile de Montréal, 17.vi.1906, Beaulieu (1 ♀, CNC); Nun’s Island, 3.vi.1925, C.R. Twinn (1 ♂, CNC). USA. New York: Ithaca, 17.v.1936, H.K. Townes (4 ♂, 1 ♀, USNM); Ithaca, 2.vi.1934 (1 ♂, USNM); McLean, 31.v.1913 (1 ♂, USNM). Pennsylvania: Centre Co., Colyer Lake, 14.vi.1975, D.D. Wilder (1 ♂, CAS).

Diagnosis. This species is distinguished by dense antero- and posteroventral rows of stout setae on basal 0.25 of hind tibia, lacking corresponding setae on hind femur; posterior margin of epandrium truncate.

Re-description. Wing length 7.0– 7.7 mm. Male. Head dark in ground-colour, with dense greyish pruinescence on face, frons and occiput. Dichoptic, eye with ommatidia of similar size. Frons divergent towards antennae; below ocellar triangle slightly wider than anterior ocellus, bearing short, dark setulae along inner margin of eye. Face slightly divergent towards mouthparts; bare with oral margin pale and shining. Ocellar triangle dark, subshining, with pair of short, parallel ocellar setae and pair of shorter posterior 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 and stylus dark; scape, pedicel and extreme base of postpedicel slightly paler or orange-brown. Scape nearly 3× longer than pedicel; postpedicel nearly 4× longer than basal width, 2.5× longer than stylus. Palpus yellow, with setulae dark. Proboscis largely reddish yellow; apex and base of labrum reddish brown; labellum with dark setae.

Thorax dark in ground-colour, largely densely grey pruinescent; apex of postpronotum and apical margin of scutellum yellowish. Scutum with pair of distinct dark, brownish vittae between acr and dc rows; pair of distinct vittae lateral to dc and above notopleural depression. Pleura grey, with yellowish margins of some sclerites. Proepisternum with several short, dark setae; prosternum bare. Antepronotum with row of short, stout dark setae. Postpronotum with 7 or more short, dark setae and 1 long seta. Scutum with inconspicuous, sparse biserial row of fine acr setulae; dc similar to acr, increasing in length posteriorly; 2 posterior npl, with several anterior npl setae; 1 presut spal; 1 psut spal; 1 pal. Scutellum with pair of short sctl, shorter than pal, with 1–2 pairs of marginal setulae. 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 and preapical setae, longer and stouter along preapical anterior margins. Hind trochanter lacking spine-like or modified setae. Fore and mid femora lacking posteroventral row of setae; subapex of hind femur thickened, with apex tapered and slightly arched; 2–3 preapical antero- and posteroventral setae; lacking preapical rows of setae as on hind tibia ( Fig. 6 D). Fore tibia clothed in long dark setae, shorter than width of tibia; several stout erect setae on dorsal and posterior faces, and apex. Mid tibia clothed in long dark setae, shorter than width of tibia; 5–6 anterior, 4 posterior, 3–5 anterodorsal, 2 posteroventral and several preapical setae. Hind tibia with 5–6 antero- and posterodorsal setae and several preapical setae; basal 0.25 with dense, antero- and posteroventral rows of dark, stout setae ( Fig. 6 D). 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 veins; all veins complete (except Sc), well sclerotized. Basal costal seta short, inconspicuous, slightly stouter and longer than surrounding costal setae. R5 and M1 somewhat parallel near wing margin; R5 ending beyond wing tip; radial fork acute. Halter yellow.

Abdomen concolorous with thorax, median area of tergites dark, sternites yellowish; marginal setae long and dark on segments 1–2 on tergites, marginal setae shorter, finer and paler on apical segments. Marginal setae on segment 8 longer and darker than preceding segment. Pregenital segments unmodified; sclerites of segment 8 narrowly separated laterally, not weakly sclerotized dorsally. Terminalia ( Fig. 7 B) largely yellow. Cercus narrow, appressed to dorsal margin of epandrium, linear, broader at anterior end; dorsal inner margin with tooth-like projection at inner apex; posterior end truncate, arched medially; clothed in setae, longer than width of cercus. Hypoproct with narrow cluster of long setae. Epandrial lamella subquadrate, posterior margin truncate, bearing long subapical setae. Hypandrium shorter than base of phallus, with rounded apical margin; base with several dark setae, shorter than hypandrium. Phallus with broad base, apical portion straight, slightly tapered; apex not emerging beyond cercus; ejaculatory apodeme nearly 0.67× length of epandrium; inverted Y-shaped, with short median keel.

Female. Similar to male, except as follows: frons slightly broader; modified setae of hind tibia lacking; cercus long and slender, slightly shorter than tergite 8.

Geographical distribution and seasonal occurrence ( Fig. 5 B). Empis (En.) ctenocnema is known from southern Quebec, New York and Pennsylvania. Adults have been collected from mid-May to mid-June.

Nuptial gift presentation. Form unknown.

Figures

FIGURE 5. Distribution of E. (Enoplempis). A, E. amytis; B, E. appalachicola and E. ctenocnema.

FIGURE 6. Male legs of E. (Enoplempis). A, E. arthritica, hindleg, anterior view; B, E. arthritica, apex of hind femur and base of hind tibia, anterior view; C, E. arthritica, apex of hind femur and base of hind tibia, posterior view; D, E. ctenocnema, hindleg, anterior view; E, E. enodis, hindleg, anterior view.

FIGURE 7. Male terminalia, lateral view of E. (Enoplempis). A, E. arthritica; B, E. ctenocnema.