Empis (Enoplempis) amytis Walker

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 : 404-407

Empis (Enoplempis) amytis Walker

(Figs 2C, D, 3A, B, C, 4A, 5A)

Empis amytis Walker, 1849: 493 . Type locality: New York, USA.

Empis longipes Loew, 1864: 76 . Type locality: New York, USA. [Preoccupied by Meigen, 1804]. syn. nov. Empis longeoblita Steyskal (in Melander, 1965: 460), n. name for longipes . syn. nov. Empis deterra Walley, 1927: 96 . Type locality: Niagara Glen, Ontario, Canada. syn. nov. Empis (Enoplempis) longipes: Melander, 1928: 142 .

Type material examined. Empis amytis : HOLOTYPE, ♀ labelled: “ Type [green bordered circle]”; “R ???/ New York [hand-written]”; “N. York [circle]”; “One of Walkers/series so named/ EAW[aterhouse]”; “Apparently insect/ referred to by Walker/ presented by/ E. Doubleday not/ Ent. Club./ E.A.W[aterhouse]. 31.3.00 ”; “ amytis ,”; “Holo-/ type [red bordered circle]”; “BMNH(E) #/ 246165” (BMNH).

Empis deterra : HOLOTYPE, ♂ labelled: “ HOLOTYPE ♂/ Empis / deterra / Walley/ CNC No. 2448 [red label]”; “Niagara Glen, Ont./ 24 - VI 1926 / G.S. Walley” (CNC). PARATYPES: Same data as holotype, except 2, 9, 24, 30.vi. –1.vii.1926 (6 ♂, 8 ♀, CNC).

Empis longipes : HOLOTYPE, ♂ labelled: “ Type / 1101 [red label with white top border]”; “Lake George”; “273”; “ longipes / m”; “ HOLOTYPE / Empis / longipes Lw. ♂/ (= longeoblita / Steyskal)/ teste WJ Turner 1981 [red label]” [dissected] (MCZ).

Additional material examined. CANADA. Ontario: Chatterton, 24.v.1954, J.C. Martin (1 ♀, CNC); Dundas, 1.vi.1978, J. Cappleman (1 ♂, CNC); Dundas, below Borer’s Falls, 43°17'25''N 79°55'60''W, 5.vi.2011, 10.vi.2012, B.J. Sinclair (1 ♂, 2 ♀, CNC); Kent Co., Rondeau PP, South Pt Tr., 42°15'42''N 81°50'49''W, savannah, MT, 29.v.– 10.vi.2003, S.A. Marshall (1 ♂, 1 ♀, DEBU); Midland, swampy woods, balsam poplar, 30.vii.1956, 2.v.1959, J.G. Chillcott (3 ♂, CNC); Ridgeway, 7.vi.1912, M.C. Van Duzee (1 ♀, CAS); Vineland, 27.v.1978, 12.vi.1980, D. Yu (1 ♂, 1 ♀, DEBU). USA. Connecticut: Kent Falls, 13.vi.1931 (2 ♂, CNC). Michigan: Emmet Co., Idlewild, 21.vii.1940, C.W. Sabrosky (1 ♂, USNM). New Jersey: Branchville, 5.vi.1932, C.H. Curran (1 ♂, 2 ♀, AMNH). New York: Colden, 23.v.1909, M.C. Van Duzee Coll. (1 ♂, CAS); Freeville, 25.v.1916 (1 ♀, USNM); Helde[r]burg Mts, 6.vi.1923, S.W. Bromley, [with prey] crane fly Limnophila subcostata (Alex.) (1 ♂, USNM); Hamburg, 26.v.1912, M.C. Van Duzee (1 ♀, CAS); Herkimer, 8.viii.1921, M.D. Leonard (1 ♂, 1 ♀, CUIC); Ithaca (3 ♂, 3 ♀, CUIC, USNM); Ithaca, 5.vi.1897 (1 ♂, USNM); Ithaca, 23.vi.1935, 17.v.–2.vi.1936, H.K. Townes (5 ♂, 4 ♀, USNM); Ithaca, 16.v.1936, W. Middlekauff (1 ♀, USNM); Ithaca, Fall Ck, 11.vi.1920, M.D. Leonard (1 ♂, CUIC); McLean Reserve nr Dryden, 11.vi.1964, J.G. Chillcott (2 ♀, CNC); Niagara Falls, 22.vi, C.W. Johnson (1 ♂, USNM); S. Wales, 23.vi.1912, M.C. Van Duzee (1 ♂, USNM); Tompkins Co., McLean Bogs, 29.v.1915 (1 ♂, CUIC); Trenton Falls, 5–8.vi.1921, Leonard & Forbes (1 ♀, CUIC). North Carolina: Jackson Co., Nantahala NF, Mull Ck Rd 1737, 19.v.1994, Kondratieff & Fitzgerald (1 ♂, CSUC). Pennsylvania: Centre Co., The Rock nr State College, 22.v.1980, D.D. Wilder (1 ♂, CAS); Spring Branch, 21.v.1945 (1 ♀, USNM). Tennessee: Sevier Co., GSMNP, Elkmont, 26.iv.2000, S.A. Marshall (1 ♀, DEBU). Virginia: Bath Co., Blowing Sprgs, Back Ck, 24.v.2002, B. Kondratieff (1 ♂, CSUC); Giles Co., Cascade Falls Tr., 19.v.1997, S.A. Marshall (2 ♀, DEBU); Madison Co., Shenandoah NP, 3000 ft., on blossoms Acer spicatum , 7.vi.1962, J.R. Vockeroth (1 ♂, 1 ♀, CNC); Smyth Co., Mt. Rogers, 4700–5300 ft., 1.vi.1962, J.R. Vockeroth (1 ♂, CNC). West Virginia: Pocahontas Co., Sharp Knob, 3500 ft., 18.v.1965, J.G. Chillcott (1 ♀, CNC); Wayne Co., 2 mi S Kenova, Big Sandy Rd (1 ♂, CSUC).

Diagnosis. This species is distinguished by the usually yellow thoracic pleura and stout spine-like setae on inner face of hind coxae in both sexes, quadrate epandrium and very long setae of the hypandrium.

Re-description. Wing length 6.8–7.8 mm. Male. Head dark in ground-colour, with dense greyish pruinescence on face, frons and occiput, except postgena yellow. Dichoptic, eye with ommatidia of similar size. Frons divergent towards antennae; below ocellar triangle as wide as or slightly wider than anterior ocellus, bearing short 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 parallel ocellar setae and pair of posterior setulae. 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; pedicel and apex of scape slightly paler or orangebrown. Scape slightly more than 2× longer than pedicel; postpedicel nearly 5× longer than basal width, 3× longer than stylus. Palpus yellow, with setulae dark. Proboscis largely yellow; apex of labrum reddish brown; labellum with dark setae.

Thorax yellow in ground-colour, largely densely grey pruinescent. Scutum with pair of distinct blackish vittae between acr and dc rows, separated by broad greyish stripe; pair of indistinct stripes lateral to dc and above notopleural depression, flanked with brown along outer margin and grey along inner margin. Pleura yellow, often with darker shadows along edges of sclerites; rarely completely greyish yellow. Proepisternum with several short, dark setae; prosternum bare. Antepronotum with row of short, stout dark setae. Postpronotum with 3–4 short, dark setae and 1 long seta. Scutum with inconspicuous, sparse row of fine acr setulae; dc similar to acr, increasing in length posteriorly; 2 posterior npl, with several anterior npl setae; presut spal absent; 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 ( Fig. 3 A). Coxae with numerous dark lateral setae, longer and stouter along apical anterior margins. Hind trochanter with partial row of 4–6 black, spine-like setae on inner face ( Fig. 3 C). Femora with posteroventral row of fine dark setae, distinct on mid femur; hind femur somewhat thickened towards apex, often with 1–3 preapical spine-like anterior setae ( Fig. 3 B). Fore tibia clothed in long dark setae, shorter than width of tibia; lacking stout erect setae except for several preapical setae. Mid tibia clothed in long dark setae, shorter than width of tibia; 3–4 anterodorsal, 2–4 anterior, 2 posterodorsal, 1–2 posteroventral and several preapical setae. Hind tibia with 4–5 antero- and posterodorsal setae, 3–4 posteroventral setae and several preapical setae ( Fig. 3 A). 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 parallel near wing margin; R5 ending beyond wing tip; radial fork acute. Halter yellow.

Abdomen yellow with long marginal setae on tergites. Marginal setae on segment 8 longer than length of sclerites. Pregenital segments unmodified; sclerites of segment 8 narrowly separated. Terminalia ( Fig. 4 A) largely yellow. Cercus narrow, appressed to dorsal margin of epandrium, linear, broader at anterior end; dorsal inner margin with tooth-like projection beyond midlength; posterior end truncate, arched medially; clothed in setae, subequal in length to width of cercus. Hypoproct with narrow cluster of long setae. Epandrial lamella subquadrate, posterior margin somewhat projecting, bearing long apical setae. Hypandrium prolonged posteriorly with rounded margin, about 0.5× as long as epandrium; base with numerous long, curled-tipped, dark setae, longer than hypandrium. Phallus with broad base, apical half Z-shaped; apex just emerging beyond cercus; ejaculatory apodeme nearly longer than epandrium; inverted Y-shaped, with short median keel.

Female. Similar to male, except as follows: frons slightly broader; spine-like setae of hind trochanter sometimes less numerous and slightly less stout; cercus long and slender, slightly shorter than tergite 8.

Geographical distribution and seasonal occurrence ( Fig. 5 A). Empis (En.) amytis is known from Michigan, southern Ontario and New York, south along the Appalachian Mountains to Tennessee and North Carolina. Adults have been collected from late April to late July.

Nuptial gift presentation. A male specimen from Helderburg Mountains, New York (see “Additional material examined”) was found with a crane fly prey item pinned below the specimen. This probably indicates that males of this species present unwrapped prey to females as nuptial gifts.

FIGURE 2. Wings and tarsi of E. ( Enoplempis ). A, E. gulosa , male wing; B, E. tridentata , male wing; C, E. amytis , male hind tarsomeres 2–5, ventral view; D, E. amytis , male hind tarsus, lateral view; E, E. nodipoplitea , male hind tarsus, lateral view. Abbreviations: bm-m—basal medial crossvein; CuA—anterior branch of cubital vein; cua—anterior cubital (= anal) cell; CuP—posterior branch of cubital vein; dm—discal medial cell; dm-m—discal medial crossvein; M1, M2, M4—medial veins; R1, R2+3, R4, R5—radial veins; Sc—subcostal vein; t—tarsomere.

Figures

FIGURE 3. Male legs of E. (Enoplempis). A, E. amytis, hindlegs, anterior view; B, E. amytis, hind femur, anterior view; C, E. amytis, hind coxae and trochanters, anterior view; D, E. appalachicola, foreleg; E, E. appalachicola, hindleg, anterior view.

FIGURE 4. Male terminalia, lateral view of E. (Enoplempis). A, E. amytis; B, E. appalachicola. Abbreviations: cerc—cercus; ej apod—ejaculatory apodeme; epand—epandrium; hypd—hypandrium; ph—phallus.

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