Wing length 3.6–4.1 mm (♂), 4.3 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.7. Eye height divided by gena height: 3.6–5.3 (up to 10.0 in German material examined). First flagellomere slightly elongate with distal margin covered with tuft of dense, pale hairs. Fronto-orbital plate and parafacial slightly produced, curving under eye as distinct cheek. Ocellar triangle hemispherical in outline. Epistoma relatively large to narrow. Thorax and abdomen with light greyish pruinosity.

Chaetotaxy : Three ori, two ors. Four to six dorsocentrals (four in Nearctic specimen), slightly decreasing in size anteriorly (more so presuturally). Mid tibia with two posteromedial setae.

Colouration : Body dark brown with halter white and gena and parafacial light brown; lunule, pedicel, scape and frons (between narrow fronto-orbital plates) brownish orange; first flagellomere orange with deeper brown tint past base, sometimes mostly brown; palpus brownish; posterior 1/3–1/2 of frons sometimes darker; ocellar triangle dark brown, distinct, slightly larger than tubercle; notopleuron slightly paler than rest of notum. Calypter margin and hairs white. Examined European material with paler parts of head lighter orange, parafacial and posterior parts of frons darker, thorax reddish, palpus reddish orange and lunule yellow. Wing veins light brown; coxae and femora paler brown with apices of latter yellow; tibiae and tarsi light brownish orange.

Genitalia : (Figs 139–142) Surstylus entirely fused to epandrium and with several tubercle-like setae on inner face (concentrated posteriorly). Hypandrium produced at apex. Postgonite broad and flat apically with inner-medial swelling. Phallophorus elongate and narrow, interlocking and partially fused to basiphallus. Left 1/2 of basiphallus short, arising apically from phallophorus; right 1/2 of basiphallus broad basally and with thin curved apical section; apices of both halves abruptly converging. Hypophallus small and membranous with lightly sclerotised medial section. Mesophallus not much longer than wide, rounded and slightly flattened basally, and with several basal, lateral and anteromedial extensions; distiphallus separate, not much longer than wide, cup-like with internal fringe of hairs and basal 1/2 more abruptly narrowed. Ejaculatory apodeme asymmetrical, with distal margin irregular and medial rib offset and annulated.

Boraginaceae – Aegonycho, Amsinckia (?), Anchusa, Asperugo, Borago, Brunnera, Buglossoides, Cerinthe, Cynoglossum, Echium, Lappula, Lindelofia, Lithospermum, Lycopsis, Myosotis, Nonea, Omphalodes, Onosma, Pentaglottis, Pulmonaria, Podonosma, Pulmonaria, Solenanthus, Symphytum (Spencer 1976; Benavent-Corai et al. 2005; Ellis 2021).

USA: VA*. Europe.

Syntypes [abiens]: Sweden. Scania ad Tranas, Esperod, Ostra Torp. [Not examined – one ST labeled as lectotype (Spencer, 1963d)]

Syntypes [echii]: Germany [not given]. [Not examined]

England. Hampstead, 26.vi.1954, em. 2.viii.[19]54, CNC352640 (1♀, CNC). Germany. Thuringen: H. Buhr, mine an Cynoglossum officinale, vii.1964, Hering, CNC352639, No. 2034 (1♂ 1♀ [with puparia], CNC). Europe. [illegible], 20.vii.1953, em. 11.viii.[19]53, CNC352638 (1♂, CNC), [illegible] viii.1908 (2♂ 1♀, USNM). USA. VA: Strausberg, 21.ix.1980, W.H. Rowe (1♂, USNM).

The Virginia male recorded here is the first Nearctic instance of this otherwise European species, which feeds on a wide range of Boraginaceae. The irregular, uneven basiphallus, the distinct mesophallus and the cup-like distiphallus with an inner fringe of hairs are characteristic. Externally, this species is relatively large with a white male calypter, it has five fronto-orbitals, a relatively pale head and the apical third of the first flagellomere is densely covered in pale hairs. Morphology is incredibly similar to Agromyza pseudoreptans Nowakowski, which also occurs in Europe and North America and may occur in the Delmarva states, but the distiphallus is distinctly longer than wide (not as long as wide) and is similarly constricted dorsoapically (not broadly domed, as illustrated in previous works).

Wing length 2.1–2.9 mm (♂), 2.5–3.5 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.8. Eye height divided by gena height: 3.6–5.6. First flagellomere relatively elongate with dorsoapical corner slightly pointed; velvety with small apical tuft of dense pale hairs (only distinct when viewed anteriorly). Fronto-orbital plate and parafacial slightly pronounced, curving under eye as cheek. Ocellar triangle reaching level of anterior ors, sides concave.

Chaetotaxy : Two ors, two or three ori (if three, anterior seta smaller). Four postsutural dorsocentrals, anterior two much shorter. Mid tibia with two posteromedial setae.

Colouration : Body black with halter white and wing veins paler and fore knee sometimes very narrowly yellow. Calypter margin and hairs white. Faint greenish shine sometimes evident, mostly on abdomen.

Genitalia : (Figs 143–146) Surstylus broad and triangular, entirely fused to epandrium, margin darkly pigmented, setae clustered at apex and inner margin with several medial to subapical tubercle-like setae. Inner lobe of hypandrium with furrows leading to base of setae. Postgonite small, flat, lobe-like. Halves of basiphallus converging to point of fusion at base; apices abruptly converging; right 1/2 with long membranous extension at midpoint. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution), with sides parallel medially, one pair of elongate parallel dark ventromedial swellings, and a slightly broadened apical margin with inner surface minutely spinulose; slightly angled dorsally.

Poaceae – Triticum aestivum (only known North American host), Agrostis, Arrhenatherum, Brachypodium, Bromus, Calamagrostis, Dactylis, Deschampsia, Festuca, Glyceria, Hordeum, Milium, Phalaris, Phalaroides (Ellis 2021), Phleum, Poa, Secale, Setaria. In Europe, most commonly occurring on Phalaria arundinacea, Hordeum and Poa (Spencer and Steyskal 1986b; Benavent-Corai et al. 2005).

Canada: AB, BC, MB, NB*, NL, NS*, NT, NU*, ON, QC, SK*, YT*. USA: AK, CA, CO, DC*, IA, IL, MA, MD*, MI, NC*, NY, OH, PA*, SC*. Widespread in Palaearctic (Černý et al 2020).

Syntype [albipennis]: Austria [not given] (1♀, NMW). [Not examined].

Syntype [dubitata]: USA. MA: Beverly (1♀, USNM; two females reported in Spencer and Steyskal 1986b).

[dubitata]: Canada. QC: Beaulieu, Ile de Montreal, 14.vii.1906 (1♀, USNM), Ottawa [illegible], Beaulieu, 20.vii.1912, “13” (1♀, USNM), Cottage Beaulieu, Beaulieu, 16.vii.1906, “15” (1♀, USNM), Cottage Beaulieu, Beaulieu, 21.viii.1906, “19” (1♀, USNM), Cottage Beaulieu, Beaulieu, 10.vi.1906, “21 0” (1♀, USNM). USA. MA: Beverly, 23.viii.1969 (1♀, USNM).

Syntypes [albo-hyalinata]: “Ovasa ad Esperod Scaniae… Dania” (? ZIL). [Not examined].

Holotype [albipennis fennica]: Finland. Messuby (1♂, UZMH). [Not examined].

Canada. AB: Black Foot Hills, 9.viii.1940, A.R. Brooks, CNC352861 (1♀, CNC), Lethbridge, 27.vi.1923, H.L. Seamans, CNC352860 (1♀, CNC), Banff Natl. Pk., Lk. Louise, 1402 m, 7.vii.1955, R. Coyles, CNC352693 (1♀, CNC), Banff, Jasper Hwy, Sunwapta Pass, 2011 m, 7.vii.1955, R. Coyles, CNC352692 (1♀, CNC), Elkwater, 11.vi.1956, CNC352652 (1♂, CNC), Onefour, 49°6'0"N, 110°24'0"W, 4.vi.1955, J.R. Vockeroth, CNC352653, CNC352654 (2♂, CNC), Elk Island N.P. Wood Bison Trail wetland alongside aspen forest, lots of tall grass, 53.5666°N, 112.8514°W, 722 m, BIOBus, 1.vii.2012, BIOUG06731-D05 (1♂, CNC), Waterton Lakes NP, Highway 6 pulloff east of 2 Flags Lookout montane forest, douglas fir and lodgepole pine (mostly conifer with aspen/birch understory), 49.065°N, 113.7781°W, 1562 m, BIOBus, 11.viii.2012, BIOUG06502-C07 (1♀, CNC), BC: Liard Hot Spg. Mi496 Alaska Hwy, 457 m, 9–10.vii.1959, E.E. MacDougall, CNC352698 (1♀, CNC), Moosehorn Lake, 58°10'0"N, 132°7'0"W, 1371 m, 25.vii.1960, R. Pilfrey, CNC352658 (1♂, CNC), Summit L., Mi392 Alaska Hwy, 1402 m, 16.vii.1959, E.E. MacDougall, CNC352699 (1♀, CNC), Terrace, 10.vi.1960, 5.vi.1960, C.H. Mann, CNC352655, CNC352656, CNC352657, CNC352697 (3♂ 1♀, CNC), Vernon, 3.ix.1931, R.D. Bird, CNC352651, 2s37, IV 31 (1♂, CNC), Bobson, 6.v.1952, H.R. Foxlee, CNC352862 (1♀, CNC), Oliver, 20.v.1923, C.B. Garrett, CNC352863 (1♀, CNC), Vernon, 31.vii.1937, H. Leech, CNC352864 (1♀, CNC), Victoria, 20.v.1919, W. Downes, CNC352844 (1♂, CNC), MB: Minnedosa, 5mi N, 8.vii.1958, R.L. Hurley, CNC352690 (1♀, CNC), Shilo, 5mi SW, 28.v.1958, R.B. Madge, CNC352663 (1♂, CNC), Western MB, Riding Mountain Nat. Pk. – North Escarpment Trailhead wet meadow/marsh, 50.674°N, 99.65°W, 726 m, J. Straka, J. Crossey, 15.viii.2008, 08BDIP-1973 (1♀, CNC), Aweme, 26.vi.1916, N. Criddle, CNC352842 (2♂, CNC), 28.viii.1917, CNC352843 (1♂, CNC), NB: Kouchibouguac N.P., 8.vii.1977, J.F. McAlpine, Code-6020N, CNC352688, CNC352689 (2♀, CNC), NL: Gros Morne; Gros Morne Mountain Hiking Trail, 49.5657°N, 57.8324°W, 39 m, J. Crossey, R. Labbee, A. Smith, M. Zhang, 15.vii.2009, 09BBEDI-0938 (1♀, CNC), St. John’s, Agric. Exp. Sta., 12.vii.1967, 15.vii.1967, J.F. McAlpine, CNC353033, CNC353041, CNC353042 (2♂ 1♀, CNC), NS: Kentville, 22.viii.1912, from tortricid larva on apple, [illegible], CNC352650 (1♂, CNC), NT: Ft. McPherson, 19.vii.1957, R. Hurley, CNC352695 (1♀, CNC), NU: [N.W.T.] Muskox L., 64°45'0"N, 108°10'0"W, 2.viii.1953, J.G. Chillcott, CNC352696 (1♀, CNC), ON: Almonte, 18.v.1951, J.F. McAlpine, CNC352679 (1♀, CNC), Hailerbury, 12.viii.1947, G.S. Walley, CNC352646 (1♂, CNC), Marmora, 1.vi.1952, 13.v.1952, J.C. Mitchell, J.R. Vockeroth, CNC352674, CNC352675, CNC352676 (3♀, CNC), Maynooth, 25.v.1951, J.F. McAlpine, CNC352677 (1♀, CNC), Minnedosa, 5mi N, 8.vii.1958, R.L. Hurley, CNC352691 (1♀, CNC), Normandale, 42°42'0"N, 80°19'0"W, 27.v.1956, J.R. Vockeroth, CNC352645 (1♂, CNC), 29.v.1956, J.R. Lonsway, CNC352678 (1♀, CNC), Ottawa, 8.vii.1952, G.E. Shewell, CNC352647 (1♂, CNC), Port Hope, 25.v.1925, N.K. Bigelow, CNC352680 (1♀, CNC), Port Severn, 3mi N, 18.v.1959, J.G. Chillcott, CNC352681 (1♀, CNC), Putnam, 26.vi.1925, G.S. Walley, CNC352644 (1♂, CNC), St. Williams, 42°40'0"N, 80°25'0"W, 23.v.1956, J.R. Vockeroth, CNC352649 (1♂, CNC), Turkey Pt., 42°39'0"N, 80°21'0"W, 25.v.1956, J.R. Vockeroth, CNC352683 (1♀, CNC), Brockville, 5.viii.1903, W. Metcalfe, CNC352847 (1♀, CNC), Cottage Beaulieu, 16.vii.1906, 145, CNC352854 (1♀, CNC), Mer Bleue, 10.v.1938, G.E. Shewell, CNC352834 (1♂, CNC), Norway Point, Lake of Bays, 31.vii.1919, J. McDunnough, CNC352851 (1♀, CNC), Orillia, 18.vii.1923, C.H. Curran, CNC352848 (1♀, CNC), 17.viii.1923, CNC352850 (1♀, CNC), Ottawa, 15.vii.1938, A. Brooks, CNC352830 (1♂, CNC), Ottawa, 11.ix.1947, G.E. Shewell, CNC352829 (1♂, CNC), Ottawa, A. Brooks, 5.vii.1938, CNC352852 (1♂, CNC), Ottawa, 27.vii.1912, Beaulieu, CNC352853 (2♂ 2♀, CNC), Pt. Ryerse, 1.vi.1939, G.E. Shewell, CNC352835 (1♂, CNC), St. Johns, Little Montreal River, 9.vii.1937, G.E. Shewell, CNC352855 (1♀, CNC), Simcoe, 8.vi.1939, G.E. Shewell, CNC352849 (1♀, CNC), Simcoe, G.E. Shewell, 14.vi.1939, CNC352831 (1♂, CNC), Simcoe, G.E. Shewell, 22.vi.1939, CNC352832 (1♂, CNC), Simcoe, G.E. Shewell, 29.v.1939, CNC352833 (3♂ 1♀, CNC), Metcalfe, 2mi N, 10.vi.1982, B.E. Cooper, CNC353037 (1♂, CNC), Metcalfe, 25.v.1983, B.E. Cooper, CNC353038 (1♂, CNC), Ottawa, damp second-growth Acer-Betula wood, 15.viii.2003, 20.vii.1974, 29.vi.1991, J.R. Vockeroth, CNC353032, CNC353035, CNC353036 (2♂ 1♀, CNC), Port Severn, 3mi N, black spruce bog, 18.v.1959, J.G. Chillcott, CNC353039, CNC353034 (2♂, CNC), QC: Ile de Montreal, 7.vii.1906, Beaulieu, CNC352837 (1♂, CNC), Old Chelsea, 13.vi.1961, J.R. Vockeroth, CNC353040 (1♂, CNC), St. Johns, Little Montreal River, 9.vii.1937, G.E. Shewell, CNC352836 (1♂, CNC), Wakefield, 9.vii.1946, G.E. Shewell, CNC352838 (1♂, CNC), Woburn, 19.vi.1923, C.H. Curran, CNC352859 (1♀, CNC), Aylmer, 16.vii.1959, C.H. Mann, CNC352684 (1♀, CNC), Farnham, 5.vi.1963, J.R. Vockeroth, CNC352642, CNC352682 (1♂ 1♀, CNC), Hull, 20.vi.1956, J.R. Vockeroth, CNC352685 (1♀, CNC), Indian House L., 20.vii.1954, 27.vi.1954, 27.vii.1954, R. Coyle, R. Coyles, W.R. Richards, CNC352648, CNC352686, CNC352687 (1♂ 2♀, CNC), Knowlton, Bolton Pass, 243 m, 5.vi.1963, J.R. Vockeroth, CNC352641 (1♂, CNC), Mt. Orford, 365 m, 5.vi.1963, J.R. Vockeroth, CNC352643 (1♂, CNC), Abbotsford, G. Shewell, 29.v.1936, CNC352839, CNC352858 (1♂ 1♀, CNC), Abbotsford, 10.viii.1937, G.E. Shewell, CNC352840 (1♂, CNC), Abbotsford, G. Shewell, 20.viii.1936, CNC352841 (1♂, CNC), 30.v.1936, CNC352857 (1♀, CNC), Abbotsford, 20.v.1931, J.B. Maltais, CNC352856 (3♂ 3♀, CNC), SK: Christopher L., 27.viii.1948, A.R. Brooks, CNC352705, CNC352706 (2♀, CNC), Val Marie, 49°15'0"N, 107°44'0"W, 5.vi.1955, 9.vi.1955, J.R. Vockeroth, CNC352659, CNC352662, CNC352664, CNC352665, CNC352666, CNC352700, CNC352701, CNC352702, CNC352703, CNC352704, CNC352707 (5♂ 6♀, CNC), Grasslands National Park, Visitor’s Center grass cattle pasture, 49.246°N, 107.732°W, 812 m, J. Cossey, N. Jeffery, J. Straka, 14.vii.2008, 08BBDIP-2742 (1♂, CNC), Saskatoon, 12.vii.1940, 22.vii.1939, 25.v.1926, 25.viii.1923, 28.ix.1925, sf. wheat, A.P. Robinson, K.M. King, King, 13288; D679; ‘41, 1328B; D676; ‘41, 1328B; D677, 1328B; D678, 16410- 3N9B, 16423 1229B; D348, 16425 26BS5; D350, 63AN, D663, CNC352845, CNC352846, CNC352865, CNC352866, CNC352867, CNC352868, CNC352869, CNC352870, CNC352871 (2♂ 7♀, CNC), YT: Otter Lake, 1219 m, 15.vii.1960, J.E. H. Martin, CNC352694 (1♀, CNC). USA. AK: Anchorage, 18.vi.1951, 3.vii.1951, IDEMA Illustration, R.S. Bigelow, CNC352668, CNC352720 (1♂ 1♀, CNC), Fairbanks, 13.vi.1952, J.B. Bartley, CNC352669 (1♂, CNC), Mackenzie Delta, Reindeer Depot, 30.vi.1948, J.R. Vockeroth, CNC352661 (1♂, CNC), Umiat, 13.vii.1959, 24.vii.1959, 5.vii.1959, 6.vii.1959, 7.vii.1959, 7.viii.1959, 9.viii.1959, IDEMA Illustration, J.E.H. Martin, R. Madge, CNC352660, CNC352667, CNC352673, CNC352712, CNC352713, CNC352714, CNC352715, CNC352716, CNC352717, CNC352718, CNC352719 (3♂ 8♀, CNC), CO: Walden, 11.viii.1965, G.F. Knowlton (1♂, USNM), Doolittle Ranch, 9800', Mt. Evans, 9.vii.1961, C.H. Mann (1♂, USNM), Doolittle Ranch, Mt. Evans, 2987 m, 3.viii.1961, 9.vii.1961, C.H. Mann, CNC352670, CNC352708 (1♂ 1♀, CNC), Boulder, 5500', 5.vi.1961, B.H. Poole (1♀, USNM), Mt. Evans, 3535 m, 11.vii.1961, C.H. Mann, CNC352711 (1♀, CNC), Mt. Evans, 3566 m, 22.vii.1961, B.H. Poole, CNC352710 (1♀, CNC), Nederland, 2529 m, 5.vii.1961, J.G. Chillcott, CNC352672 (1♂, CNC), Jackson Co., Rabbit Ears Pass, 7.vii.1961, J.G. Chillcott, CNC352671, CNC352709 (1♂ 1♀, CNC), DC: Theo Roosevlt Id, 4.vi.1977, W.N. Mathis (1♂, USNM), MA: Boston, June (1♂ 1♀, USNM), Concord, 19.vii.1961, marsh, W.W. Wirth (2♂ 3♀, USNM), Forest Hills, 21.ix.1913, A.L. Melander (2♀, USNM), MD: Colesville, 4.vii.1976, W.W. Wirth (2♀, USNM), Colesville, 14.vi.1975, Malaise trap, W.W. Wirth (1♀, USNM), NC: Macon Co., Highlands, Lake Ravenel, 7.vi.1986, Malaise trap, W.W. Wirth (1♂, USNM), NY: Ithaca, 15.viii.1926, A.L. Melander (1♂, USNM), Geneva, 28.v.1914, A.L. Melander (1♂, USNM), Long Island, Cold Spring Harbor, A.L. Melander (1♂ 2♀, USNM), Allegany State park, 28.v-3.vi.1963, mossy woods, W.W. Wirth (1♀, USNM), PA: Mineral Spr., 5.ix.1927, A.L. Melander (1♂, USNM), Chester Co., Avondale, Stroud Res. Ctr., 28.ix.2006, K. Styer (1♀, UDCC), SC: Black Falls, 7.viii.1953, A.L. Melander (1♀, USNM).

See comments for Agromyza aprilina.

Wing length 2.3–2.7 mm (♂), 2.7–3.9 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.5–0.7. Eye height divided by gena height: 2.9–3.6. First flagellomere slightly longer than wide with apex broadly rounded; without tuft of pale hairs. Fronto-orbital plate and parafacial slightly projecting. Ocellar triangle broadly rounded and short, not extending much past ocelli. Buccal cavity subquadrate with anteromedial margin emarginate.

Chaetotaxy : Four or five thinner ori with anterior seta sometimes shorter; one ors. Four postsutural dorsocentrals, decreasing in length anteriorly. Mid tibia with two posteromedial setae. Female sometimes with strong additional seta between acrostichal seta and posterior dorsocentral.

Colouration : Body predominantly brown, halter white. Gena (excluding ventral margin), parafacial and frons (excluding posterolateral corner, posterior margin and ocellar triangle) light brownish orange. Scape and pedicel yellow; first flagellomere orange with distal 1/2–2/3 brownish. Lunule orange with yellowish pilosity. Face brown. Palpus and clypeus dark brown. Tarsi yellow (slightly darker on posterior legs), fore tibia light brown and knees narrowly yellow. Calypter margin and hairs white. Female with frons darker (sometimes entirely brown or with anterior margin lighter), gena darker and fore tibia darker medially.

Genitalia : (Figs 147–151) Surstylus triangular, entirely fused to epandrium; with apical setae and medial tubercle-like setae. Hypandrium long and thin with narrow apical point. Postgonite lobate, directed apically. Phallophorus produced apically and fused to base of basiphallus. Halves of basiphallus widely bowed with bases broadly fused; elongate and narrow with margins irregular. Distiphallus very long, thin, dark, bifid, and strongly curved into semicircle at split; base of distiphallus with transverse dorsal band and paired ventral sclerites. Hypophallus large, membranous, and directed apically. Ejaculatory apodeme dark and very reduced in size.

Variation : Female from CA differs as follows: wing length 4.1 mm; anterior (of four) ori small; only three dorsocentrals; eye height divided by gena height 2.5; tibiae yellow to base and apex; gena mostly pale.

Asteraceae – Artemisia (?), Ambrosia artemisiifolia, A. trifida and probably A. douglasiana (Spencer and Steyskal 1986b; Benavent-Corai et al. 2005); Helianthus annuus (Eiseman and Lonsdale 2018).

Canada: ON. USA: CA, CO, MA, MD, NY, PA, VA*.

Holotype: Canada. ON: Pelee, em. 31.vii from leaf-mines on Ambrosia artemisifolia, leg. 8.vii.1967, CNC352722 (1♂ [with puparium], CNC).

Paratypes: Canada. ON: Pelee, K.A. Spencer, mine Ambrosia artemisifolia, 15.vii.1967, em. 1–10.viii.1967, CNC352723-CNC352744 (10♂ [5 with puparia], 12♀ [8 with puparia], CNC).

Canada. ON: Belleville, P. Harris, vii.1969, em. 22.ix.1969, CNC352721 (1♀ [with puparium], CNC), Ottawa, damp second-growth Acer-Betula woods, 8.viii.1993, J.R. Vockeroth, CNC353060 (1♂, CNC). USA. CA: Carbon Canyon, 14.vi.1977, on Artemesia d. (1♀, USNM), CO: Chaffee Co., Poncha Springs, South Arkansas River, 8.vii.2015, C.S. Eiseman, Helianthus, em. 28.vii-1.viii.2015, #CSE1872, CNC654328–654332 (1♂ 4♀, CNC), MA: Worcester Co., Sturbridge, Leadmine Rd., 6.vii.2013, em. 20.vii.2013, C.S. Eiseman, ex Ambrosia artemisiifolia, #CSE725, CNC392679, CNC392680 (2♀, CNC), MD: Plummers Isl., 30.v.1913, R.C. Shannon (1♀, USNM), College Park, 7.vii.1935, C.T. Greene (1♂, USNM), Pr. William Co., Woodbridge, 26.vii.1968, J.W. Adams (1♂, USNM), Montgomery Co., Colesville, 26.vi.1977, Malaise trap, W.W. Wirth (2♂, USNM), 30.vi.1977 (1♂, USNM), Colesville, W.W. Wirth, 4.vii.1976 (2♀, USNM), 11.vii.1974 (2♂, USNM), 24.vii.1974 (1♂, USNM), 28.vii.1976 (2♂, USNM), 1.viii.1976 (2♂, USNM), 4mi SW of Ashton, 1.ix.1981, Malaise trap, G.F. and J.F. Hevel (1♀, USNM), Bethseda, G. Steyskal, 6.vii.1970 (2♂, USNM), 7.vii.1970 (1♂, USNM), Allegeny Co., Little Orleans, Little Orleans campground, 4.vi.1999, sweeping, C.R. Bartlett (1♂, UDCC), nr. West Mifflin, Coal Valley Rd. #2, 5.vii.1997, sweeping, C.R. Bartlett (1♀, UDCC), PA: Chester Co., Pottstown, Warwick County Park, 10.viii.2014, ex. Ambrosia trifida, em. 2.ix.2014, C.S. Eiseman, #CSE1371, CNC384846 (1♀, CNC), VA: Great Falls, 21.vi.1931, A.L. Melander (1♂, USNM), Alexandria, “viii-5”, J.M. Aldrich (1♀, USNM), Fairfax Co., Turkey Run Park, nr. mouth of Turkey Run, 38°57.9'N, 7°09.4'W, Malaise trap, 18–30.v.2007, D.R. Smith (1♀, USNM), Turkey Run Park, 0.3 km W mouth Turkey Run, 38°58'N, 77°09.6'W, Malaise trap, D.R. Smith, river 14–17.v.2006 (1♂, USNM), river trap, 17–24.v.2006 (2♀, USNM), Great Falls Park, swamp trail, 38°59.4'N, 77°15.2'W, Malaise trap, trap #2, 18.iv.2.v.2007, D.R. Smith (1♀, USNM).

Agromyza ambrosivora is an easily recognised species with one pronounced ors and four or five thinner ori. The phallus forms a long, dark bifid tubule, which is very similar to that found in A. virginiensis (Fig. 151): these two species can be separated externally using the characters mentioned in the key. A third related species, A. rudbeckiana Scheffer and Lonsdale, a leaf-miner of Heliopsis and Rudbeckia (Asteraceae), has a more evenly arched distiphallus that is only split near the apex, and unlike A. ambrosivora, there are two ors and three ori (not one and four) (Scheffer and Lonsdale 2018).

Wing length 4.0–4.1 mm (♂), 4.4–4.8 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.4–0.7. Eye height divided by gena height: 2.1–2.4. Ocellar triangle small and rounded. First flagellomere small and rounded; without apical tuft of pale hairs. Fronto-orbital plate slightly projecting and parafacial strongly projecting, partially to strongly continuing under eye as cheek. Wing slightly pointed apically with apex between M1 and R₄₊₅. Thorax with light to dense grey pruinosity.

Chaetotaxy : Three to seven ori (two in Spanish female); two ors. Six or seven dorsocentrals, two or three presutural, decreasing in size anteriorly. Mid tibia without posteromedial setae.

Colouration : Body mostly dark brown. Head yellow with back of head, occiput, clypeus, mentum and ventral margin of gena dark brown, distal 2/3 of first flagellomere brownish, venter of face light brown and frons slightly darker anteriorly. Knees yellowish orange; tibiae and tarsi paler than femora with tibiae slightly darker medially. Scutum with nearly imperceptible metallic green shine in VA female. Calypter margin and hairs white to dark brown. Halter white, rarely with small lateral spot and ventral margin of knob brown (VA female). Abdomen dark brown with indistinct (VA) or strong coating of grey pruinosity, except on brownish orange male terminalia (sometimes with dark dorsomedial spot on epandrium). European specimens often with fronto-orbital plate, face, apex of palpus, parafacial and ring under eye mostly dark, tibiae often yellowish or more orange on distal 1/3, and epistoma usually larger.

Genitalia : (Figs 152–155) Epandrium relatively broad and shallow, with suture between it and surstylus barely evident. Surstylus slightly curved anteriorly and with numerous small, pointed, tubercle-like setae along inner-basal/medial surface. Phallophorus tapered distally and partially fused to flat, pale sclerites of basiphallus, which are weakest and irregular along dorsal margin, with right sclerite partially separated from darker, curved apical section. Hypophallus sac-like and membranous with partial sclerotisation along anteromedial surface. Distiphallus nearly cylindrical with irregularly sclerotised margins not entirely meeting ventrally; twisted past midpoint. Ejaculatory apodeme minute.

Asteraceae – Carduus, Cirsium, Cynara (Spencer 1990).

USA: VA*. France, Italy, Malta, Germany, Spain, Croatia (Papp and Černý 2015). Turkey. Chile (Valparaiso, La Cruz; introduced) and Argentina (Valladares 1998; Çöl et al. 2006).

Syntypes [Apfelbecki]: Yugoslavia. Zadar (♂♀, coll. Strobl). [Not examined]

Syntypes [andalusiaca]: Spain. “Southern Spain” [= Algreciras?] (?, coll. Strobl). [Not examined]

France. Perpignan, 10.x.1959, mine Cynara carduuculus, em. 24.v.1959, K.A. Spencer, CNC352745 (1♂ [with puparium], CNC). Germany[?]. “Agrom. Apfelbecki Str., det. Hendel” (1♀, USNM). Spain. Barcelona, “prat”, 27.iii.1960, K.A. Spencer (1♀, USNM), CNC352746 (1♀, CNC), En Alcachofe, La Cruz, Valpo, Nac. 5.ix.1959, N. Hichins (5♂ 2♀ 1?, USNM). USA. VA: Fairfax Co., Turkey Run Park, 0.3 km W mouth Turkey Run, 38°58'N, 77°09.6'W, Malaise trap, 29.iii-25.iv.2007, D.R. Smith (1♀, USNM).

While difficult to differentiate from a number of Palaearctic taxa, Agromyza apfelbecki is quite distinct from Nearctic Agromyza because it is exceptionally large (wing length at least 4.0 mm), there are numerous dorsocentrals (at least six), the epistoma is large and pronounced, the head is predominantly pale (including the palpus and face) and the halter is sometimes maculated. Agromyza apfelbecki is one of only three Agromyza known to feed on Asteraceae, and is distributed primarily around the Mediterranean where it often occurs on globe artichoke (Spencer, 1990).

The above Virginia record is the first known occurrence of this species in the Nearctic, where it was likely introduced accidentally on its host plant. As discussed by Dempewolf (2004), Agromyza apfelbecki can be a major pest on artichoke if populations become large enough, particularly to younger plants; the damage caused by larval feeding can vary significantly between years (Spencer 1973), possibly due to climatic conditions, as frost can severely increase mortality among larvae (Ricchello 1928).

Wing length 2.2–2.5 mm (♂), 2.5–3.2 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.8. Eye height divided by gena height: 2.2–3.4. First flagellomere slightly longer than high with rounded dorsoapical point (pronounced to relatively indistinct), without apical tuft of pale hairs. Fronto-orbital plate and parafacial projecting (more so anteriorly), continuing under eye as cheek. Ocellar triangle longer than wide and subshiny. Costa extending slightly past R₄₊₅. Smaller females with vein dm-m incomplete.

Chaetotaxy : Two ori; three ors (or vice versa), sometimes appearing as four ori and one ors. One presutural dorsocentral and three or four postsutural dorsocentrals, decreasing in length anteriorly. Mid tibia with two posteromedial setae.

Colouration : Body dark brown with halter white and gena and frons (aside from fronto-orbital plate and ocellar triangle) reddish, fore knee yellow and tarsi dirty yellow. Calypter margin and hairs white. Female from “Turkey Run, headquarters” with light green metallic shine on thorax, abdomen and pleuron (faintest).

Genitalia : (Figs 156–160) Anterodistal margin of epandrium deeply incised before surstylus. Surstylus triangular, fused to epandrium with suture evident; inner-basal margin with several small tubercle-like setae. Hypandrium slightly produced at apex, inner margin of lobe thickened with several setulae. Postgonite small and lobe-like with thin plate-like base. Phallus relatively small, narrow, and weakly sclerotised. Phallophorus tapering apically, fused to halves of basiphallus, which converge to base. Halves of basiphallus with internal fold apically, with distal portion sharply directed inwards; lateral membrane broad, twisted past midpoint. Distiphallus of "nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); nearly carinate ventromedially, distal section with elongate medial split.

Unknown.

Canada: AB, BC, MB, NB*, ON, QC, SK, YT*. USA: IL, MD*, NC*, NH, VA*.

Lectotype: USA. IL: Cottonwood Grove, Urbana, 16–20.iv.1915 (1♀, INHS). [Not examined]

USA. IL: Urbana, 20.iv.1915, Cottonwood, CNC352757, Type No. 2725 (1♀, CNC).

Canada. AB: Banff, C.B.D. Garrett, 8.vi.1922, CNC352760 (1♀, CNC), MB: Ninette, J.F. McAlpine, 21.v.1958, CNC352778 (1♀, CNC), 9.v.1958, CNC352755 (1♂, CNC), R.B. Madge, 9.v.1958, CNC352776 (1♀, CNC), Shilo, 5mi SW, J.F. McAlpine, 28.v.1958, CNC352777 (1♀, CNC), NB: Kouchibouguac N.P., Hanley and Cooper, 23.v.1977, Code-5113Q, CNC352754, CNC352774, CNC352775 (1♂,2♀, CNC), W.P. Hanley, 20.v.1977, Code-5098B, CNC352753 (1♂, CNC), ON: Bell’s Cor[ner]., J.F. McAlpine, 8.v.1951, CNC352766 (1♀, CNC), Marmora, J.F. McAlpine, 23.iv.1952, CNC352751, CNC352768, CNC352769 (1♂ 2♀, CNC), 24.iv.1952, CNC352752, CNC352767 (1♂,1♀, CNC), 25.iv.1952, CNC352772 (1♀, CNC), 28.iv.1952, CNC352770 (1♀, CNC), 29.iv.1952, CNC352773 (1♀, CNC), 9.v.1952, CNC352771 (1♀, CNC), Maynooth, J.F. McAlpine, 24.v.1951, CNC352764 (1♀, CNC), Metcalfe, B.E. Cooper, 14.v.1983, CNC353020, CNC353022 (2♂, CNC), 25.v.1983, CNC353021, CNC353024 (2♂, CNC), 27.iv.1983, CNC353019, CNC353025, CNC353026 (3♂, CNC), 3.v.1983, CNC353027 (1♂, CNC), 30.iv.1983, CNC353018, CNC353023 (2♂, CNC), 7.v.1994, CNC353028–353031 (4♂, CNC), Ottawa, 28.iv.1955, J.R. Vockeroth, CNC352765 (1♀, CNC), Woodroffe, J.G. Chillcott, 30.iv.1952, CNC352763 (1♀, CNC), QC: Abbotsford, G.E. Shewell, 27.iv.1936, CNC352747, CNC352748, CNC352750, CNC352758 (3♂,1♀, CNC), 27.iv.1966, CNC352749 (1♂, CNC), Shewell, 15.v.1936, CNC352759 (1♀, CNC), SK: Saskatoon, A.R. Brooks, 28.iv.1949, CNC352756 (1♂, CNC), 9.v.1949, CNC352762 (1♀, CNC), YT: Dawson, 14 mi E, P.J. Skitsko, 6.viii.1962, 396 m, CNC352761 (1♀, CNC). USA. MD: Montgomery Co., Plummers Island, 38°58'N, 77°10'W, Malaise trap, lower trap, 30.iii-22.iv.2006, D.R. Smith and J.W. Brown (1♀, USNM), Cabin John Bridge, 23.iv.1914, R.C. Shannon (1♂, USNM), Plummers Isl., R.C. Shannon, 8.iv.1914 (4♂ 3♀, USNM; 2♂ 2♀, CNC), 12.iv.1914 (1♂, USNM), 5.iv.1914 (1♂, USNM), 3.iv.1914 (1♂ 1♀, USNM), Plummers Island, Rock Run, 25.iii.1914, R.C. Shannon (1♂, USNM), nr. Plummers Isl., 28.iii.1915, R.C. Shannon (2♂, USNM), NC: Smokies, Andrews Bald, 9.vii.1914, A.L. Melander (1♂, USNM), VA: Fairfax Co., Turkey Run Park, nr. mouth of Turkey Run, 38°57.9'N, 7°09.4'W, Malaise trap, 29.iii-25.iv.2007, D.R. Smith (4♂ 1♀, USNM), Turkey Run Park, nr. headquarters bldg. 38°57.7'N, 77°08.9'W, Malaise trap, 29.iii-17.iv.2007, D.R. Smith (1♀, USNM), Great Falls Park, swamp trail, 38°59.4'N, 77°15.2'W, Malaise trap, trap #1, 18.iv-2.v.2007, D.R. Smith (1♀, USNM).

The surstylus and epandrium of Agromyza aprilina are characteristic, readily differentiating it from similar species. In the Delmarva states it can be most easily confused for the relatively common A. albipennis, but the ventral margin of the first flagellomere is flatter in this latter species, there are four fronto-orbitals (not five), the parafacial is not as pronounced, the setae are darker and the costa extends to vein M₁₊₂. The shape of the basiphallus and distiphallus also differ (see Figs 145, 146). While the first flagellomere can appear less pointed in some material, particularly poorly preserved specimens, it is never entirely rounded as noted in Spencer (1969).

Agromyza aprilina can also be potentially mistaken for Agromyza nigripes Meigen, but the latter has darker tarsi, the costa ends at vein M₁₊₂, and the male genitalia (based on the dissection of Welsh male in the USNM) are much stouter with slight differences in the shape of the basiphallus and distiphallus. The species A. ambigua Fallén (North America, Europe), A. kincaidi Malloch (North America; Figs 196, 197) and A. conjuncta Spencer (widespread in Europe) can also be mistaken for this species, but the characteristic phallus, surstylus and epandrium of A. aprilina allows for definitive identification. Other Nearctic Agromyza with a pointed first flagellomere and a shortened costa are restricted to the west coast and have a larger, darker distiphallus (Spencer and Steyskal 1986b).

(Fig. 37). Wing length 2.0–2.1 mm (♂), 2.3–2.4 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.9. Eye height divided by gena height: 1.9–2.7. First flagellomere subcircular, without apical tuft of pale hairs. Fronto-orbital plate (more so anteriorly) and parafacial strongly projecting and distinctly continuing under eye as cheek. Ocellar triangle relatively small with corners rounded. Palpus relatively ovate.

Chaetotaxy : Two ori; two ors. Ocellar seta thinner than postocellar, and sometimes shorter, but never reaching 1/2 length. Three postsutural dorsocentrals, decreasing in length anteriorly; possibly two more anteriorly that are not much longer than surrounding setulae. Acrostichal seta not much longer than surrounding setulae. Four scattered rows of acrostichal setulae. Mid tibia without posteromedial setae.

Colouration : Head predominantly light yellow; first flagellomere yellow; back of head brown above foramen and with grey pruinosity dorsally; ocellar triangle dark brown; posterolateral corner and posterior margin of frons brownish, with spot extending laterally to just behind level of anterior ors; clypeus light brown; face white. Thorax dark brown, covered with grey pruinosity, halter white. Calypter margin and hairs white to yellow. Legs yellow with mid and hind coxae brown, at least in part. Abdomen dark brown; epandrium yellow or with orange to brown tint with dark brown dorsal spot; if epandrium yellow, sternite 8 sometimes also yellow with medial spot.

Genitalia : (Figs 161–166) Surstylus fused with epandrium with suture obliterated, shape triangular (nearly equilateral), directed inwards, with several setae along posterior margin. Cercus relatively broad and flat with inner surface covered with pointed tubercle-like setae. Hypandrium setulose, slightly sinuate, and inner lobe with medial desclerotisation. Postgonite short. Phallophorus fused to single sclerite of basiphallus, which originates on left side and is twisted dextrally. Hypophallus membranous with faint left lateral sclerotisation. Mesophallus long, narrow, dark, and flat, lying along ventral margin of membrane; distiphallus short, flat and wrapped ventrally (nearly cylindrical), shortest dorsally. Ejaculatory apodeme minute and finger-like.

Cannabaceae – Celtis laevigata, C. occidentalis, C. pallida (leaf mine only); Ulmaceae – Ulmus alata (leaf mine only), U. americana, U. rubra (Eiseman et al. 2021).

Canada: AB, NB*, ON, QC*. USA: IL, IN, IA, KS*, MI*, NY, OH, PA, VA, VT; known from leaf mines in AL, AR, CO, CT, FL, GA, MA, MD, MN, ND, NJ, TN, TX, WI.

Holotype [aristata]: USA. IL: Havana, Gleason’s Sand Dune, 30.iv.1914, C.A. Hart and J.R. Malloch (HT ♀, INHS). [Not examined]

[aristata]: USA. IL: St. Joseph, Salt Fork, 3.v.1914, Type No. 2726, CNC352790 (1♀, CNC), PA: Arendtsville, 27.iv.1923, S.W. Frost (3♂, USNM).

Syntype [ulmi]: USA. PA: Arendtsville, 22.iv.1923, S.W. Frost (1♂, USNM; type No. 50033).

Holotype [marmorensis]: Canada. ON: Marmora, 7.v.1952, J.R. Vockeroth (HT ♂, CNC).

Canada. AB: Onefour, on wild cherry blossom, 2.vi.1956, O. Peck, CNC353069, CNC353072, CNC352809 (2♂,1♀, CNC), NB: Curventon, 19.v.1959, W.W. Moss, C-2, CNC352810 (1♀, CNC), ON: Almonte, 18.v.1951, J.F. McAlpine, CNC352788, CNC352803–352806 (1♂,4♀, CNC), Marmora, 16.v.1952, J.C. Mitchell, CNC352786 (1♂, CNC), 30.iv.1952, J.F. McAlpine, CNC352802 (1♀, CNC), Marmora, 28.iv.1952, J.F. McAlpine, CNC352787 (1♂, CNC), Metcalfe, 14.v.1994, B.E. Cooper, CNC353066 (1♂, CNC), 17.v.1994, CNC353067 (1♂, CNC), 7.v.1994, CNC353068 (1♂, CNC), Midland, swampy wood, 26.v.1959, J.G. Chillcott, CNC353071 (1♂, CNC), Nippising, 27.ii.1959, #83, S58-1-1381-01, CNC352779 (1♂, CNC), Ottawa nr. Uplands Airport, 22.v.1990, J.M. Cumming, CNC353064 (1♂, CNC), Ottawa, damp second-growth Acer-Betula wood, 1.vi.1995, J.R. Vockeroth, CNC353063 (1♂, CNC), 28.v.1995, CNC353070 (1♂, CNC), at sap on Acer stump, 10.v.1991, J.R. Vockeroth, CNC353062 (1♂, CNC), bleeding elm, 22.v.1952, J.F. McAlpine, CNC352791 (1♀, CNC), 28.v.1951, J.F. McAlpine, CNC352794 (1♀, CNC), 5.v.1952, B. Hartley, CNC352783 (1♂, CNC), J.G. Chillcott, CNC352783–352795, CNC352780, CNC352792 (2♂,3♀, CNC), 8.v.1952, J. Chillcott, CNC352782, CNC352785, CNC352796–352800 (2♂,5♀, CNC), Pt. Pelee, 3.vi.1929, G.S. Walley, CNC352801 (1♀, CNC), QC: Hemmingford, 10.v.1931, J.B. Maltais, CNC352807 (1♀, CNC), Old Chelsea, 8.v.1938, G.E. Shewell, CNC352808 (1♀, CNC). USA. IL: White Heath, 30.iv.1916 (1♀, USNM), Champaign, 28.iv.1953, J.F. McAlpine, CNC352789 (1♂, CNC), IN: Lafayette, J.M. Aldrich, 4.v.1916 (1♂, USNM), 11.v.1916 (1♀, USNM), KS: Manhattan, C.W. Sabrosky, 27.iv.1934 (1♀, USNM), 17.vi.1934 (1♀, USNM), Lawrence, Nat. Hist. Res., 27.iii.1954, J.G. Chillcott, CNC352781 (1♂, CNC), 28.v.1956, J.G. Chillcott, CNC352811–352818 (8♀, CNC), MI: Detroit, 24.v.1935, G. Steyskal (1♂, USNM), E Lansing, C. Sabrosky, 2.vi.1934 (1♀, USNM), 29.iv.1942 (1♀, USNM), NC: Scotland Co., Laurinburg, St. Andrews University, 18.iv.2017, T.S. Feldman, Celtis laevigata, em. ~17.iv.2018, #CSE4418, CNC1144090 (1♀, CNC), OK: Payne Co., Mehan, 36.014339°N, 96.996744°W, 5.iv.2016, em. by 11.iv.2017, M.W. Palmer, ex Ulmus rubra, #CSE3448, CNC939912 (1♂, CNC), VA: Chain Bridge, 23.iv.1922, J.R. Malloch (1♀, USNM), Fairfax Co., Great Falls Park, quarry, 38°59.1'N, 77°14.8'W, Malaise trap, D.R. Smith, 18–23.iv.2007 (2♀, USNM), 13–24.v.2007 (1♀, USNM), VT: USA. Vermont: Chittenden Co., South Burlington, Winooski Gorge, 16.v.2015, C.S. Eiseman, Ulmus rubra, em. 24.iii-6.iv.2016, #CSE2264, CNC654497–654499 (3♀, CNC).

The dissected paratype of Agromyza aristata discussed by Spencer (1969) has been examined and the genitalia are identical to those of the male illustrated here, not as illustrated in Spencer (1969). The unusual illustration in Spencer (1969) appears to belong instead to a non-type male in the USNM from Illinois that has had the phallus broken off near the base of the mesophallus. This mistake in interpreting the male genitalia led Spencer to describe A. marmorensis in the same revision, stating that while "Not satisfactorily distinguishable from A. aristata” based on external characters, the differences in the genitalia were significant enough to separate them. Since it is now clear that the genitalia of the two species are also identical, A. marmorensis is here included as a junior synonym of the senior A. aristata.

The new records for NB, QC, MI and KS represent new adult records, but these were previously suspected from leaf mines (Eiseman et al. 2021).

(Figs 38, 41, 42). Wing length 2.2–2.4 mm (♂). Female unknown [see discussion below]. Length of ultimate section of vein M4 divided by penultimate section: 0.5–0.7. Eye height divided by gena height: 4.2–6.0. Male first flagellomere large (usually at least 30% longer than pedicel, but not much longer than pedicel in a minority of specimens) and varying in shape from elongate and subovate to (more commonly) circular; at least distal 1/2 (usually distal 2/3) covered with long hairs. Ocellar triangle relatively small with corners slightly rounded. Fronto-orbital plate slightly projecting.

Chaetotaxy : Two ori; two ors. Three dorsocentrals, decreasing in length anteriorly with anterior seta not much longer than surrounding setulae. Mid tibia with two posteromedial setae.

Colouration : Body primarily dark brown with halter white. Base of first flagellomere and distal margin of pedicel orange; orange region sometimes either extending to basal 1/3 of first flagellomere or strongly reduced (particularly if spines on surstylus reduced). Gena sometimes paler, excluding ventral margin. Calypter white with margin sometimes yellowish or slightly brown, and hairs light brown. Base of fore tibia paler or segment paler overall. Tarsi yellow to orange-brown.

Genitalia : (Figs 167–173) Surstylus small, lobate, margin darkly pigmented; with two or three medial setae and two large posterior spines; spines sometimes minute and rounded and distiphallus more elongate with relatively pronounced internally haired medial section; surstylus barely visible when viewed laterally and with basal suture obliterated. Hypandrium relatively narrow and tapered apically with membranous window in lobe. Postgonite relatively small and upcurved. Halves of basiphallus converging to, and overlapping at base; with small mediolateral membranous lobe on each sclerite; twisted medially and broad apically, with converging ventrodistal points. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); relatively narrow and pale with sides parallel, being only slightly wider apically.

Variation : Phallus sometimes elongate with pronounced medial section with densely spinulose inner surface and elongate medial membranous projection on right sclerite of mesophallus (Fig. 174); if so, spines on epandrium reduced to absent. Possibly a new species, but “typical” males show intermediate degrees of spine reduction on epandrium that resemble the state seen in these other males.

Poaceae – Elymus hystrix (Eiseman and Lonsdale 2018).

Canada: ON, MB*. USA: CT*, GA, IA, MD, NC, NH*, NY, PA*, UT, VA, WV*.

Holotype: Canada. ON: Simcoe, 5.vi.1939, G.S. Steyskal (1♂, CNC).

Paratypes : Canada. ON: Midland, 20.vii.1955, J.G. Chillcott, CNC352821 (1♂, CNC), Pt. Ryerse, 1.vi.1939, G.E. Shewell, CNC352822, (1♂, CNC), Simcoe, 5.vi.1939, G.E. Shewell, CNC352819 (1♂, CNC).

Canada. MB: Ninette, 28.vii.1958, “sq. fringe darker spines on surs. larger aed. larger”, J.G. Chillcott, CNC352820 (1♂, CNC). USA. CT: Redding, 11.vi.1929, A.L. Melander (1♂, USNM), Rabin Co., 13.vii.1957, W.R. Richards, CNC352824 (1♂, CNC), IA: Winneshiek Co., 43°25'55.97"N, 92°0'34.78"W, 16.vii.2015, C.S. Eiseman, Elymus hystrix em. 7.viii.2015 , #CSE1973, CNC564662 (1♂, CNC), MD: Bethseda, 30.v.1980, G.C. Steyskal, swept ex. Viola papilionaceae (2♂, USNM), Bethseda, 14.v.1981, G.C. Steyskal (1♂, USNM), 11.viii.1981 (1♂, USNM), 14.viii.1981 (2♂, USNM), 16.viii.1981 (1♂, USNM), 1.viii.1981 (3♂, USNM), 17.v.1969 (1♂, USNM), 7.viii.1981 (2♂, USNM), 13.ix.1981 (1♂, USNM), 27.v.1972 (1♂, USNM), Plummers Isl., 19.vi.1913, R.C. Shannon (1♂, USNM), Montgomery Co., Dickerson, 14.vii1974, G.A. Foster (13♂, USNM), 4mi SW of Ashton, G.F. and J.F. Hevel, 16.viii.1986 (1♂, USNM), 24.vii.1982 (1♂, USNM), 27.viii.1981 (1♂, USNM), Cabin John, 20.vi.1931, A.L. Melander (1♂, USNM), NC: Macon Co., Wayah Gap, 3800', 29.vii.1957, J.G. Chillcott (1♂, USNM), Jackson Co., Cherokee, 609 m, 25.vii.1957, CNC352823 (1♂, CNC), NH: Bretton Wda, 1.vii.1936, A.L. Melander (1♂, USNM), PA: Allegeny Co., Little Orleans, Little Orleans campground, 6.vi.1998, sweeping, C.R. Bartlett (1♂, UDCC), VA: Falls Church, Holmes Run, 26.vi.1961, light trap, W.W. Wirth (1♂, USNM), Shenandoah, Big. Meadows, A.L. Melander, 1.vii.1939 (1♂, USNM), 2.vii.1939 (2♂, USNM), 5.vii.1939 (1♂, USNM), Great Falls, 9.vii.1926, A.L. Melander (1♂, USNM), Glencarlyn, 2.vi.1925, J.R. Malloch (1♂, USNM), Fairfax Co., Dead Run, 22.vi.1916, R.C. Shannon (1♂, USNM), Fairfax Co., Turkey Run Park, nr. mouth of Turkey Run, 38°57.9'N, 7°09.4'W, Malaise trap, 18–30.v.2007, D.R. Smith (1♂, USNM), WV: Parkersburg, 21.vi.1970, G. Steyskal (1♂, USNM), Morgan Co., nr. Great Cacapon, 1.ix.1984, G.F. and J.F. Hevel (1♂, USNM), Hardy Co., Lost River St. Pk., 1–14.viii.1960, K.V. Krombein (1♂, USNM).

USA. CT: Colebrook, 28.viii.1941, A.L. Melander (1♀, USNM), MD: Coleville, W.W. Wirth, 21.v.1977 (1♀, USNM), 11.v.1977 (1♀, USNM), NC: Macon Co., Wayah Bald, 1066 m, 13.vii.1957, W.R. Richards, CNC352828 (1♀, CNC), Macon Co., Wayah Gap, 16.vii.1957, J.G. Chillcott, CNC352827 (1♀, CNC), NH: Franconia Notch, 8.vii.1931, J.M. Aldrich (1♀, USNM), NY: Ithaca, 31.v.1914, A.L. Melander (3♀, USNM), TN: Smokies, Chimneys, 25.vi.1941, A.L. Melander (1♀, USNM), VA: Falls Church, 18.vii.1960, W.W. Wirth (1♀, USNM), Shenandoah, Big Meadows, A.L. Melander, 3.vii.1939 (1♀, USNM), 2.vii.1929 (1♀, USNM), Shenandoah, Lewis falls, 3.vii.1939, A.L. Melander (1♀, USNM), Fairfax Co., Dead Run, 28.vii.1915, R.C. Shannon (1♀, USNM), Shenandoah Co., Mt. Jackson, 25.v.1962, J.G. Chillcott, J.R. Vockeroth, CNC352825, CNC352826 (2♀, CNC).

Agromyza bispinata belongs to a complex of species defined by an enlarged and long-haired male first flagellomere, whose species appear to be separable only on the basis of male genitalic morphology. The females of these species, which are currently indistinguishable from one another, differ from the males in having an elongate oval first flagellomere with the long pale hairs restricted to the distal margin; the examined females are listed in the material examined section for this species. The sparse, long hairs on the first flagellomere of these species (Figs 41, 42) should not be confused with the discrete apical tuft of hairs characteristic of many other Agromyza species, including A. canadensis, A. kincaidi, and A. pudica (see Figs 39, 40). This complex currently includes A. echinalis in the east Nearctic, A. hockingi Spencer in Canada and the western United States (but expected in the eastern United States), and the widespread A. tacita and A. bispinata. There is a relatively large amount of genitalic variation within the latter two species, including distiphallus morphology in A. bispinata and epandrial spine number in A. tacita, which suggests the presence of cryptic taxa. The presence of only two epandrial spines, which is likely the derived state, currently defines A. bispinata within this group, but more rigorous analysis of the clade as a whole is required to better delineate species.

(Figs 1, 2, 7–10). Wing length 3.1–3.9 mm (♂), 3.3–4.0 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.5–0.7. Eye height divided by gena height: 4.2–7.3. First flagellomere small and rounded; pale tuft of apical hairs varies from teardrop-shaped to encompassing distal 1/3 of segment. Ocellar triangle relatively small with corners rounded.

Chaetotaxy : Three or two ori; two ors. Five dorsocentrals (sometimes small fifth seta indistinct), decreasing in size anteriorly. Mid tibia with two posteromedial setae.

Colouration : Setae brown. Body predominantly brown with yellowish tint or yellow with brownish tint, with thorax darker and halter white. First flagellomere dark brown to brown and scape and pedicel yellow to brownish; face and lunule dirty yellow in ON specimens; gena (excluding ventral margin), parafacial (excluding inner margin) and anterior margin of postgena light brown in female; postpronotum and notopleuron yellowish in part; lateral and sometimes apical margins of scutellum and postsutural scutum yellow in females and some males. Pleuron paler brown with venter darker and posterior region yellowish; metanotum yellow with brown mottling and dark brown mediotergite; males sometimes darker. Calypter margin and hairs white. Legs yellow with faint brownish tint; tarsi sometimes paler and femora sometimes slightly darker. Abdomen brownish yellow, paler in female with dorsum sometimes brownish and oviscape brown.

Genitalia : (Figs 175–178) Surstylus indistinct, fused to epandrium; inner surface with many small, rounded tubercle-like setae not reaching anterior corner. Hypandrium relatively narrow with apex pointed; inner lobe small, rounded and with large separate medial sclerite closely associated with postgonite. Postgonite large and flat with partial fusion to hypandrial band; with sparse hairs on outer face. Halves of basiphallus flat, wide and poorly sclerotised; apices broad, converging past internal subapical fold. Distiphallus very large, resembling a thick band with anterior and posterior margins strongly curled outwards; basal portion with small, shallow lateral sculpturing. Ejaculatory apodeme well-developed basally, but reduced, thin and pale apically.

Boraginaceae – Cynoglossum, Mertensia (Benavent-Corai et al. 2005).

Canada: ON, QC*. USA: CA, VA*.

Holotype: Canada. ON: Cottage Beaulieu, Beaulieu, 14.viii.1906 (1♀, USNM).

Canada. ON: Hawkeston, 28.vi.1927, C.H. Curran, CNC353079 (1♂, CNC); Mer Bleu[e], 5mi E Ottawa, 9.vi.1966, D.D. Munroe, CNC353082 (1♂, CNC), Ottawa, Montfort Hosp., 17.vii.1993, J.R. Vockeroth, CNC353074 (1♂, CNC), Ottawa, 18.viii.1924, G.S. Walley, CNC353081 (1♀, CNC), damp second-growth Acer-Betula woods, 17.viii.2000, J.R. Vockeroth, CNC353075 (1♀, CNC), 30.v.1958, J.R. Vockeroth, CNC353078 (1♂, CNC), 30.vi.1958, J.R. Vockeroth, CNC353080 (1♂, CNC); damp second-growth Acer-Betula woods, 6.viii.1996, J.R. Vockeroth, CNC353073 (1♂, CNC), QC: Burnett, 13.viii.1977, J. O’Hara, CNC353076 (1♀, CNC), Old Chelsea, 11.vi.1959, J.R. Vockeroth, CNC353077 (1♀, CNC). USA. VA: nr. Plummers Island, 20.v.1914, R.C. Shannon (1♂, USNM), Giles Co., Ripplemead, White Riverbend Pk., 37°19'N, 80°41'W, 9.v.2006, S.A. Marshall (1♀, DEBU), Fairfax Co., Great Falls Park, quarry, 38°59.1'N, 77°14.8'W, Malaise trap, D.R. Smith, 24.iv-2.v.2007 (4♀, USNM), 3–10.v.2007 (12♀, USNM).

Agromyza canadensis is highly similar to the Palaearctic A. pseudorufipes Nowakowski, especially with regards to the derived structure of the phallus. It is also a borage feeder on Myosotis, Podonosma and Trigonotis (Benavent-Corai et al. 2005). Von Tschirnhaus (1993) suggested that the two species could be conspecific, but additional study is required.

(von Tschirnhaus 2017: figs 6–9). Wing length 3.4 mm (♂). Female unknown. Length of ultimate section of vein M4 divided by penultimate section: 0.4. Eye height divided by gena height: 4.5. Ocellar triangle not much larger than tubercle. Orbital plate narrow, inner margin weakly defined. Epistoma present, margin straight, as long as width of first flagellomere. Ventral margin of gena relatively straight, shallow anteriorly and deep posteriorly. Scutum densely matt. Costa extending to M1. Tibiae without medial setae

Chaetotaxy : Ocellar and postvertical setae strong. Two ori (three ori on right side), decreasing in length anteriorly; two ors. Minute interfrontals anteromedially on frons. Four dorsocentral setae on left side, five on right, decreasing in length anteriorly. Acrostichal seta strong. Acrostichal setulae in six irregular rows. Two or three anepisternal setae, four or five katepisternals.

Colouration : Setae dark brown. Mostly dark brown. Face, parafacial, gena and postgena (to point above midpoint of eye) and mouthparts yellowish white with dark brown line along venter of gena; lunule and antenna pale yellow with arista brown; frons light yellow with brownish/orange tint, with ocellar triangle and posterolateral corner of frons dark brown, faded brownish region around ocellar triangle, with brownish stripe along orbital plate almost to base of posterior ori, becoming indistinct anteriorly. Apices of femora and bases of tibiae narrowly yellow. Halter white with stem faintly brownish anteriorly. Calypter margin and hairs brown.

Genitalia : (von Tschirnhaus 2017: figs 1–3, 5) Cercus large, bent on outer margin and straight on inner; inner-distal surface with numerous pointed tubercle-like setae. Surstylus fused to epandrium, indistinct, without tubercle-like setae. Hypandrium subtriangular; apex rounded with narrow, pointed apodeme that may be 2 × as long as wide; inner lobe with basal section narrowing to point of attachment to thicker, angled distal section bearing row of several sockets, one of which has a moderately long seta. Postgonite with minute setulae in irregular double row; shape presumably similar to that of A. aristata. Phallophorus narrow, width < 1/3 length. Basiphallus dorsally fused to phallophorus on narrow dorsal/left lateral sclerite, which is apically truncated; right lateral sclerite much narrower, but as long as left sclerite. Paraphallus and hypophallus absent. Ejaculatory duct becoming broader along length of basiphallus, thick along mesophallus. Mesophallus a single band-like ventral sclerite partially fused to distiphallus; nearly as long as basiphallus, strongly curved to form a shallow semicircle. Distiphallus very shallow, band-like, and ventrally curved, obliquely angled. Ejaculatory apodeme unknown.

Cannabaceae – Celtis occidentalis (von Tschirnhaus 2016).

USA: CT, NY, WV.

Holotype: USA. CT: Orange, gall on twig of Celtis occidentalis, W.H. Patton. [1 gall, Lost]

USA. WV: Morgan County ca. 6 mi NW Hedgesville, 39°37'N, 78°03'W, ex twig swelling gall Celtis occidentalis, coll. 6-v-1998, em. 15-iii-1999, R. J. Gagné (1♂, USNM). [not examined]

The adult of this species was thoroughly described in von Tschirnhaus (2016), which also provided a discussion on related species, host usage, and treatment in the literature.

Wing length 2.9–3.3 mm (♂), 2.9–3.8 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.8. Eye height divided by gena height: 6.1–-9.7. First flagellomere sometimes slightly longer than high; with teardrop-shaped tuft of pale hairs at apex.

Chaetotaxy : Two ori; two ors. Three or four dorsocentrals, decreasing in length anteriorly. Mid tibia with two or three posteromedial setae.

Colouration : Setae black. Body yellow, except as follows: head mostly dark brownish with yellow tint, with mouthparts light yellow, lunule yellow, fronto-orbital plate (narrow) sometimes yellowish to yellow, gena (excluding ventral margin) and face light brown, and ocellar tubercle sometimes yellowish around base of ocellar and postocellar setae; postpronotum, notopleuron and scutellum pale yellow/whitish; halter white; female with oviscape dark brown and face yellow. Calypter margin and hairs white.

Genitalia : (Figs 179–182) Surstylus not distinguishable from epandrium; inner face of surstylus flat and covered with numerous small, rounded tubercle-like setae that do not extend to anterior corner. Postgonite relatively large, flat, and broad. Halves of basiphallus long and narrow, with right sclerite bent at midpoint; apices not bent inwards. Hypophallus convoluted and with scalloped apical fringe and irregularly sclerotised base. Mesophallus subcylindrical, with sides bulging and with transverse dorsal band; closely associated with distiphallus, which is bulging medially, truncated apically and with subapical constriction.

Urticaceae – Laportea canadensis.

Canada: ON. USA: IA, IL, IN, IN, MA, MD*, NC, NY, OH, TN, VA, VT.

Holotype: USA. MA: Chester, 7.viii.1912, C.W. Johnson (1♀, MCZ).

USA. IN: Lafayette, viii.1912, J.M. Aldrich, Paratype No. 50034 U.S.N.M. / CNC Type No. 16287, CNC352872 (1♀, CNC).

Canada. ON: Simcoe, 26.vi.1939, G.E. Shewell, CNC352873 (1♀, CNC). USA. OH: Delaware Co., Sunbury, Monkey Hollow Rd., 13–15.ix.2014, ex. Laportea canadensis, em. 16–24.x.2014, C.S. Eiseman, #CSE1432, CNC384847, CNC384848 (1♂ 1♀, CNC), IA: Ames, Pammel Woods, W.H. Robinson, 24.vi.1970 (2♂, USNM), 9.viii.1969 (1♂, USNM), 19.vi.1970 (1♂, USNM), Ames, Pammel Woods, 11.vi.1970, R.M. Miller (1♀, USNM), Ames, 1.viii.1969, W.H. Robinson (1♂, USNM), Allamakee Co., 3mi ESE Waterville, 43°11.0'N, 91°14.1'W, 2.viii.1960, J. Laffoon (1♂, USNM), Boone Co., Ledges State Park, 14.vii.1971, R.M. Miller (1♀, USNM), IL: University of Illinois Woods, 2.vii.1945, “X 526” (1♂, USNM), 15.vii.1945, “X 527” (1♂, USNM), MD: Montgomery Co., Dickerson, 14.vii.1974, G. Foster (1♂, USNM), OH: Delaware Co., Sunbury, Monkey Hollow Rd., 13–15.ix.2014, em. 16–24.x.2014, C.S. Eiseman, ex Laportea canadensis, #CSE1432, CNC384847, CNC384848 (1♂ 1♀, CNC), NC: Graham Co., Poplar Cove, 2500', 35°21.3'N, 83°56.1'W, 20.vi.1958, J. Laffoon (1♀, USNM), NY: Ithaca, 15.vi.1932 (1♀, USNM), TN: Davidson Co., Nashville, West Meade Waterfall (36.094655, -86.913252), 21.viii.2017, em. 15–17.ix.2017, C.S. Eiseman, ex Laportea canadensis, #CSE4273, CNC939958–939960 (1♂ 2♀, CNC), VA: Fairfax Co., Dead Run, 28.vii.1915, R.C. Shannon (1♀, USNM).

Externally as described for A. bispinata except as follows: Wing length 2.5–2.6 mm (♂). Female unknown. Length of ultimate section of vein M4 divided by penultimate section: 0.6. Eye height divided by gena height: 4.2. First flagellomere always enlarged in male, broadly ovate, slightly longer than high and covered with long hairs past base. Additional ori sometimes present on one side of frons. Wing veins yellow. Antenna orange with brownish tint, mostly brownish past base of first flagellomere; frons tinted with orange; fore tibia yellow with centre brownish.

Genitalia : (Figs 232–235) Surstylus large and triangular with numerous long spines along inner margin and with one spine at apex; basal suture obliterated, inner surface flat and easily viewed posteriorly. Hypandrium and postgonite as described for A. bispinata. Halves of basiphallus with medial membranous process that is longer and truncated on right side. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); ventral curve with dark truncated elbow; ventral surface with medial longitudinal suture; sides shallowly rounded and internally spinulose subapically.

Unknown.

USA: MD, TN, VA.

Gr., referring to the characteristic spiny surstylus.

Holotype: USA. TN: Clarksville, 13.v.1936, E.W. Howe (1♂, USNM).

Paratypes: USA. MD: nr. Plummers Isl., 6.vi.1914, R.C. Shannon (1♂, CNC), VA: Fairfax Co., Dead Run, 19.vi.1915, R.C. Shannon (1♂, USNM).

The heavily spinulose surstylus of Agromyza echinalis is the primary defining feature that distinguishes it from other species with an enlarged first flagellomere. As in A. tacita (Figs 226–228) and A. hockingi (Colorado, Texas, Utah; Spencer and Steyskal 1986b: figs 411–413), the surstylus is triangular and clearly visible laterally, but these other two species have a slightly darker and more rounded surstylus with a maximum of five stout spines.

(from Eiseman and Lonsdale 2018). Wing length 2.3 mm (♂). Female unknown. Length of ultimate section of vein M4 divided by penultimate section: 1.0. Eye height divided by gena height: 3.9. First flagellomere small and rounded, without pale tuft of hairs. Fronto-orbital plate slightly projecting (more so anteriorly). Ocellar triangle small and rounded. Thorax with light pruinosity.

Chaetotaxy : Two ori; two ors. Three strong dorsocentrals, anterior seta 2/3 length of second. Mid tibia without posteromedial setae.

Colouration : Setae black. Body mostly dark brown. Head yellowish orange with first flagellomere infuscated on distal 2/3, back of head and occiput dark brown, frons dark brown behind level of hind fronto-orbital, face white and clypeus brown to dark brown. Calypter margin and hairs brown. Halter white. Tarsi, base of fore tibia and apex of fore femur yellow.

Genitalia : (Figs 183–187) Surstylus small, lobate, setulose, and slightly angled anteriorly; fused to anteroventral margin of epandrium with suture partially evident. Cercus broad and emarginate apically; inner surface covered with numerous small tubercle-like setae. Postgonite small and rounded with shallow inner lobe. Single sclerite of basiphallus fused to phallophorus on left side, twisted dextrally; distal margin forming small transverse sclerite. Mesophallus small and flat. Distiphallus composed of a single dark, flat, curved sclerite (shortest dorsally) nearly forming a complete tube; lateral margins fringed and not meeting ventrally.

Cannabaceae – Celtis occidentalis (Eiseman and Lonsdale 2018).

USA: IA, MD, OK, WI.

Holotype. IA: Allamakee Co., Red Oak Prairie (43°14'13.43"N, 91°7'8.58"W), 16.vii.2015, em. 2.viii.2015, C.S. Eiseman, ex Celtis occidentalis, #CSE1925, CNC564711 (1♂, CNC).

Paratypes. IA: same collection as holotype, CNC564712 (1♂, CNC), MD: Plummers Isl., 23.v.1914, R.C. Shannon (1♂, USNM), OK: Payne Co., Mehan, 36.014339°N, 96.996744°W, 5.iv.2016, em. 20– 22.iv.2017, M.W. Palmer, ex Celtis occidentalis, #CSE3529, CNC939918, CNC939919 (1♂ 1♀, CNC); WI: Buffalo Co., Alma, S1287 State Road 88, 17.vii.2015, em. 3.iv.2016, C.S. Eiseman, ex Celtis occidentalis, #CSE2311, CNC634841 (1♂, CNC).

Although largely similar to Agromyza varifrons, the male cerci are highly derived and diagnostic: they are strongly widened apically and deeply cleft, with small, tubercle-like setae covering the inner surface.

Wing length 2.3 mm (♂), 2.5–2.7 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.7. Eye height divided by gena height: 4.8–7.5. First flagellomere small and rounded; without pale tuft of apical hairs. Ocellar triangle only indicated laterally as subshiny regions.

Chaetotaxy : Two ori; two ors. Four strong dorsocentrals, one presutural. Mid tibia with one posteromedial seta.

Colouration : Setae golden-brown, distinct from scutum. Scutum with brownish grey pruinosity. Calypter margin and hairs white (brown in isolata holotype). Body predominantly brown with halter white; base of first flagellomere and most of pedicel distinctly orange, entirely dark in isolata holotype; BC, CA, and CO material with first flagellomere dark, with basal margin slightly lighter; tarsi, tibiae (hind tibia brownish medially) and apices of femora yellow. Wing veins light brown.

Genitalia : (Figs 188–192) Surstylus broad, not distinct from epandrium and with a number of medial tubercle-like setae along inner-distal margin on posterior 1/2. Hypandrium relatively narrow with long, tapered tip. Postgonite small and dome-like. Phallophorus elongate and produced on left side, fusing with single sclerite of basiphallus. Basiphallus short, shallowly curved and restricted to dorsal surface. Mesophallus curved in cross-section, dark, and with long, bifid, tapering “tail”, with bases either separated or fused; distiphallus short, dark, and cap-like. Ejaculatory apodeme relatively small, blade pale.

Salicaceae – Populus spp., Salix spp. (Eiseman and Lonsdale 2018).

Canada: AB, BC*, ON, NS*, QC, SK. USA: CA, CO, MN [leaf mine only], PA, VA*, VT, WA.

Holotype [isolata]: USA. CA: Eureka, “22.5”, H.S. Barber (1♀, USNM; type No. 17573).

Holotype [populoides]: Canada. SK: Regina, em. 23.viii.1965, [ex leaf mine on Populus deltoides ♀ X P. balsamifera ♂ (Spencer, 1969)], ex Gracillarid sp., RRD W65, Ex 2616(10), G.N. Still (1♂ [with puparium], CNC).

[populoides]: Canada. ON: Grand Bend, 20.vii.1939, G.E. Shewell, CNC352879 (1♂, CNC), Ottawa, em. 28.vii.1967, mine Pop. Bals. 10.vii.1967, CNC352880 (1♀ [with puparium], CNC), SK: same data as holotype CNC352875–352878, CNC352881-CNC3528884 (4♂ 4♀ [seven with puparia], CNC).

Canada. BC: Terrace, grass, clover and buttercups, 7.vi.1960, R. Pilfrey, sweeping, CNC353092 (1♂, CNC), Wasa Lk., em. 29.vii.1959, “59-6779-01”, “Populus trichocarpa”, “R’rd”, CNC353083, CNC353084 (2♂ [with puparia], CNC), NS: S. Harbour Bch., PG962943, 6.vii.1983, J.R. Vockeroth, CNC353091 (1♂, CNC), ON: Grand Bend, 20.vii.1939, G.E. Shewell, CNC353089 (1♂, CNC), Ottawa, 15.ix.1997, J.R. Vockeroth, CNC353090 (1♂, CNC), 16.ix.1952, CNC353088 (1♀, CNC). USA. CO: Doolittle Ranch, Mt. Evans, 2987 m, 3.viii.1961, C.H. Mann, CNC353085 (1♂, CNC), J.G. Chillcott, CNC353087 (1♀, CNC), Summit L. Flats, Mt. Evans, 3901 m, 24.vii.1961, C.H. Mann, CNC353086 (1♂, CNC), VA: Falls Church, reared 25.v.1916, Populus, host: underside tentminer, J.J. deGryse (1♂ 2♀, USNM), VT: Chittenden Co., South Burlington, Winooski Gorge, 29.vi.2014, ex. Populus tremuloides, em. 15.vii.2014, C.S. Eiseman, #CSE1176, CNC384839–384841 (3♂, CNC), Chittenden Co., Williston, Mud Pond, 28.viii.2016, C.S. Eiseman, Populus grandidentata, em. 18–19.ix.2016 , #CSE3000, CNC654500–654504 (2♂ 3♀, CNC).

(Figs 39, 40). Wing length 3.6–4.0 mm (♂), 3.9–4.3 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.7–0.8. Eye height divided by gena height: 2.9–3.2. First flagellomere small and rounded with small apical tuft of pale hairs. Ocellar triangle 1/2 length of frons, shape equilateral or more tapered apically. Buccal cavity subquadrate and clypeus broad. Costa only extending to R₄₊₅. Thorax with light pruinosity.

Chaetotaxy : Two ori; two ors. Four postsutural dorsocentrals, one presutural, decreasing in length anteriorly. Mid tibia with two posteromedial setae.

Colouration : Body dark brown with halter white. Gena slightly paler posteriorly. Fore tarsus, apex of fore femur and base of tibiae yellowish. Wing veins light brown. Calypter margin and hairs white. Female fronto-orbital plate slightly paler and less pruinose.

Genitalia : (Figs 193–197) Surstylus not strongly differentiated from epandrium, which has deep desclerotised anteroventral emargination; with numerous posterior and medial tubercle-like setae and with rounded inner-distal point bearing several small setae. Hypandrium gently arched, not produced apically; inner lobe largely membranous and with two furrows ending in one setula each. Postgonite small, flat and lobate. Halves of basiphallus folded inwards near apex; right sclerite shorter and fused to enlarged distal margin of phallophorus. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); distal portion dark and extremely elongate with wide ventral furrow (dark medial ridge within furrow); inner surface with pronounced spinulose ridge; dorsal surface covered by dark membranous sheath. Ejaculatory apodeme broad and well-developed with distal margin pale and rib pronounced.

Unknown – likely a grass-feeder, possibly on Bromus purgans (Spencer and Steyskal 1986b).

Canada: AB, BC, MB, NL, NS, YT. USA: AK, CA, CO, IA*, NC*, NY*, TN, UT.

Holotype: USA. AK: Juneau, 25.vii.1899, Kincaid (1♀, USNM; type No. 15565).

Canada. AB: Banff, Johnston Canyon, 1432 m, 18.vii.1962, K.C. Herrmann, CNC352900, CNC352937 (1♂,1♀, CNC), 30–31.vii.1962, CNC352938 (1♀, CNC), Banff, 19.vii.1922, E. Hearle, CNC353102 (1♂, CNC), Calgary, 20 mi W, Jumping Pd. Cr., 9.viii.1962, K.C. Hermann, CNC352901 (1♂, CNC), Wate[illegible], 15.vii.1923, H.L. Seamans, CNC352903 (1♂, CNC), BC: Bowser, 8.vi.1955, R. Coyles, CNC352936 (1♀, CNC), Kleanza Cr., 14 mi E Terrace, 4.vii.1960, C.H. Mann, CNC352942 (1♀, CNC), Mt. Thornhill nr. Terrace, 1066 m, in boggy seepage area, 14.vii.1960, J.G. Chillcott, CNC352933 (1♀, CNC), Pr. Rupert, Ledum-Kalmia bog, 4.iv.1960, R. Pilfrey, CNC352935 (1♀, CNC), 4.vi.1960, C.H. Mann, CNC352896, CNC352897 (2♂, CNC), Robson, 24.v.1950, H.R. Foxlee, CNC352928 (1♀, CNC), Summit Lake, Mi392 Alaska Hwy., 1280 m, 31.vii.1959, R.E. Leech, CNC352898 (1♂, CNC), Summit Lake, 1280 m, 21.vii.1959, R.E. Leech, CNC352899 (1♂, CNC), Terrace, Airport area, 4.viii.1960, C.H. Mann, CNC352934 (1♀, CNC), Terrace, 11.viii.1960, W.R. Richards, CNC352895 (1♂, CNC), 67 m, 15.viii.1960, B. Heming, CNC352929 (1♀, CNC), 67 m, 8.vi.1960, W.W. Moss, CNC352932 (1♀, CNC), 19.vii.1960, C.H. Mann, CNC352931 (1♀, CNC), 20.vii.1960, W.R. Richards, CNC352885 (1♂, CNC), 31.iv.1960, R.J. Pilfrey, CNC352894 (1♂, CNC), 31.v.1960, C.H. Mann, CNC352930 (1♀, CNC), 31.vi.1960, J.G. Chillcott, CNC353099 (1♂, CNC), MB: Churchill, 14.vii.1952, E.F. Pope, CNC352939 (1♀, CNC), Churchill, 58°46'N, 94°10'W, 5.viii.1952, J.G. Chillcott, project#NBP, CNC_Diptera59120 (1 ex, CNC), Deer River, mile 473 m Hudson Bay Ry., 3.viii.1952, J.G. Chillcott, CNC352886 (1♂, CNC), Int. Peace Gardens, Turtle Mtn. For. Res., 7.viii.1958, J.G. Chillcott, CNC352940 (1♀, CNC), NL: Bell Is., 4–7.viii.1967, J.F. McAlpine, CNC353108 (1♂, CNC), Lab., Cartwright, 20.vii.1955, E.F. Cashman, CNC352941 (1♀, CNC), St. John’s, Agric. Exp. Sta., 1.viii.1967, J.F. McAlpine, CNC353111–353113, CNC353117 (4♂, CNC), 15.vii.1967, J.F. McAlpine, CNC353126 (1♂, CNC), 16.vii.1967, J.F. McAlpine, CNC353124, CNC353110 (1♂,1♀, CNC), on Ranunculus, 18.vii.1967, J.F. McAlpine, CNC353103–353107 (5♂, CNC), Abies balsamea, 19.vii.1967, J.F. McAlpine, CNC353109 (1♀, CNC), 21.vii.1967, J.F. McAlpine, CNC353131, CNC353135 (2♂, CNC), 24.vii.1967, J.F. McAlpine, CNC353119 (1♀, CNC), 26.vii.1967, J.F. McAlpine, CNC353133 (1♂, CNC), 27.vii.1967, J.F. McAlpine, CNC353128 (1♂, CNC), 29.vii.1967, J.F. McAlpine, CNC353120, CNC353129 (1♂,1♀, CNC), 3.viii.1967, J.F. McAlpine, CNC353114–353116 (3♂, CNC), 30.vii.1967, J.F. McAlpine, CNC353121, CNC353125 (1♂,1♀, CNC), 31.vii.1967, J.F. McAlpine, CNC353130 (1♂, CNC), 9.viii.1967, J.F. McAlpine, CNC353118, CNC353122, CNC353123, CNC353127, CNC353132, CNC353134, CNC353136 (4♂,3♀, CNC), NS: Lockeport, Cranberry I., 24.vii.1958, J.R. Vockeroth, CNC352902 (1♂, CNC), YT: Ogilvie Mts., North Fork Crossing, 1.vii.1962, P.J. Skitsko, CNC352893 (1♂, CNC), Rampart House, 67°25'N, 140°59'W, 17.vii.1951, J.E.H. Martin, project#NBP, CNC_Diptera109349 (1♀, CNC), Whitehorse, 24.viii.1959, R. Madge, CNC352926, CNC352927 (2♀, CNC). USA. AK: Anchorage, 18.vii.1951, R.S. Bigelow, CNC352915 (1♀, CNC), Cold Bay, on tundra, 18.viii.1952, W.R.M. Mason, CNC352892 (1♂, CNC), Curry, 29.vi.1952, W.R. Mason, CNC352914 (1♀, CNC), King Salmon, Naknek, 13.vii.1952, J.B. Hartley, CNC352921, CNC352923, CNC352925 (3♀, CNC), 16.viii.1952, CNC352919 (1♀, CNC), 3.vii.1952, CNC352917 (1♀, CNC), 31.vii.1952, CNC352924 (1♀, CNC), 5.viii.1952, CNC352916 (1♀, CNC), 6.vii.1952, CNC352918, CNC352920, CNC352922 (3♀, CNC), Mile 315 Richard. Hwy., 8.vi.1951, W.R. Mason, CNC352913 (1♀, CNC), Naknek, 18.vii.1952, J.B. Hartley, CNC352910, CNC352911 (2♀, CNC), 8.vii.1952, J.B. Hartley, CNC352907 (1♀, CNC), W.R. Mason, CNC352912, CNC352908, CNC352909 (3♀, CNC), CO: Doolittle Ranch, Mt. Evans, 2987 m, 22.vii.1961, J.G. Chillcott, CNC352905 (1♀, CNC), 3.viii.1961, W.R.M. Mason, CNC352888 (1♂, CNC), B.H. Poole, CNC352906 (1♀, CNC), Echo L., Mt. Evans, 3230 m, 25.vii.1961, C.H. Mann, CNC352904 (1♀, CNC), IA: Ames, 10.v.1947, A.R. Brooks, CNC352943 (1♀, CNC), NC: Gt. Smokies, Clingmans Dome, A.L. Melander, 18.vii.1941 (4♂ 3♀, USNM), 19.vii.1941 (4♂, USNM), 21.vi.1941 (1♂, USNM), Smokies, Andrews Bald, 9.vii.1941, A.L. Melander (2♂ 1♀, USNM), Smokies, Forney Ridge, 26.vi.1941, A.L. Melander (1♂, USNM), Clingman’s Dome, Grt. Sm. Mt. Nat. Park, 6.viii.1957, C.J. Durden, CNC352891 (1♂, CNC), 2011 m, 22.viii.1957, J.G. Chillcott, CNC352887 (1♂, CNC), NY: White Face Mt., 4000', 14.vii.1958, A.L. Melander (1♂, USNM), TN: Indian Gap to Clingman’s Dome, Gr. Sm. Mt. Nat. Park Tenn., 1584–2011 m, 6.viii.1957, J.G. Chillcott, CNC352889, CNC352890 (2♂, CNC).

Agromyza kincaidi is highly similar in appearance to the European and Nearctic A. ambigua Fallén (Spencer and Steyskal 1986b: figs 367–369), which has a highly similar phallus, an anterodorsally pointed first flagellomere (sometimes very strongly pointed in A. ambigua), a costa that extends just past R₄₊₅ and dark colouration. While never directly compared, differentiation between the two has historically relied most heavily on the colour of the calypter margin and hairs, which are supposedly brownish in A. kincaidi and bright white to yellow in A. ambigua (Spencer 1969); vein colour does not appear to be yellowish in any A. ambigua examined, as noted in Spencer and Steyskal (1986b); examination of specimens further reveals calypter margin/hair colour to range from yellowish to brownish, and is even white in some material identified by Spencer. The limits of these two species should be re-evaluated in the future.

Wing length 2.3–2.4 mm (♀). Male unknown. Length of ultimate section of vein M4 divided by penultimate section: 0.6. Eye height divided by gena height: 1.6. Head as described for A. aristata except parafacial not as strongly projecting and ocellar seta 1/2 length of postocellar seta.

Chaetotaxy : As described for A. aristata, except there are four dorsocentrals (one presutural), not three.

Colouration : As described for A. aristata except as follows: setae yellow; first flagellomere yellow with basal 1/3 very pale; posterolateral corner of frons only dark to level of posterior (not anterior) ors.

Variation : Florida specimen (head mostly collapsed) with ocellar seta ~ 2/3 length of postocellar and fronto-orbital plate brown to base of anterior fronto-orbital.

Unknown – possibly Celtis occidentalis (Ulmaceae).

Canada: ON*. USA: DC, FL*.

Holotype: USA. DC: Rock Creek Park, 29.v.1922, J.R. Malloch (1♀, USNM).

Canada. ON: Ottawa, Arboretum, adult on Celtis occidentalis, 27.v.2017, O. Lonsdale, CNC799468–799471 (4♀, CNC). USA. FL: Torreya St. Park, 29.iv.1952, O. Peck, on wood mud flat, CNC352944 (1♀, CNC).

The grey pruinose notum, yellow setae and head of Agromyza pallidiseta make it an easily recognised, albeit uncommon, species in eastern North America, known only from the holotype, one Florida female and four Ontario females. The Ontario females were taken as adults on Celtis occidentalis.

The Californian female listed as Agromyza pallidiseta in Spencer and Steyskal (deposited in the USNM) is clearly not conspecific with the holotype, as it is 2 × as large (4.6 mm), has a longer ocellar seta and brown setae.

Wing length 2.5–2.7 mm (♂), 2.4–2.7 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.8. Eye height divided by gena height: 3.5–6.7. First flagellomere small and rounded; males with small tuft of apical hairs (as wide as base of arista in specimens with entirely white calypter, and several times width of base of arista in males with darker calypter hairs); females with dark calypter also with wide tuft of hairs on first flagellomere. Ocellar triangle short and equilateral in female, longer in male. Scutum shiny to subshiny.

Chaetotaxy : Two ori (sometimes small to well-developed additional anterior ori on one side); two ors. Two well-developed dorsocentrals and one or two much smaller setae anteriorly. Mid tibia with two posteromedial setae.

Colouration : Body dark brown with halter white, lunule and gena (excluding ventral margin) paler, tarsi dirty yellow and tibiae sometimes yellow at base. Wing veins light brown. Calypter margin white with hairs brown to white.

Genitalia : (Figs 198–204) Surstylus with weak basal suture and numerous small medial and apical tubercle-like setae on inner margin. Inner lobe of hypandrium broad with several furrows leading to empty sockets. Postgonite small and lobate. Both sclerites of basiphallus with thin mediolateral membranous lobes; apices typically incurved. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); distiphallus split ventromedially with dark subbasal swelling and central ridge; with spinulose inner structures and minute anterodorsal scales; seen ventrally, sides nearly parallel or segment narrowest apically (mostly in specimens with white calypter hairs).

Poaceae – Dichanthelium clandestinum, D. scoparium, Glyceria canadensis, G. striata (Eiseman et al. 2021).

USA: CT*, DC*, IA, MA, MD*, NC, NH*, NJ*, NY*, TN.

Holotype: USA. NC: Mitchell Co., Roan Mtn., 6200', 13.viii.1957, J.G. Chillcott, CNC352945 (1♂, CNC).

Paratype: USA. NC: Same data as holotype, CNC352946 (1♀, CNC).

USA. CT: Putnam Park, 20.vii.1939, A.L. Melander (1♂, USNM), Redding, 3.vi.1935, A.L. Melander (2♀, USNM), DC: 11.vi.1926, J.M. Aldrich (1♂, USNM), IA: Allamakee Co., Footbridge Farm, 22.vii.2018, J. van der Linden, Poaceae, em. by 14.viii.2018, #CSE4946, CNC1643675–1643677 (2♂ 1♀, CNC), MA: Concord, 17.vii.1961, W.W. Wirth (2♂ 1♀, USNM), Lavale, 9.v.1970, G. Steyskal (1♂, USNM), Hampshire Co., Pelham, Arnold Rd., 2.vii.2013, C.S. Eiseman, ex Dichanthelium clandestinum em. 20–22.vii.2013, #CSE724, CNC392666, CNC392667 (1♂,1♀, CNC), em. 20–23.iv.2014, #CSE1089, CNC384728, CNC384729 (2♀, CNC), Plymouth Co., West Bridgewater, Maple St., 15.viii.2013, C.S. Eiseman, ex Dichanthelium clandestinum em. 2–5.ix.2013, #CSE866, CNC392683–392687 (2♂ 3♀, CNC), MD: Colesville, W.W. Wirth, 4.vi.1977 (1♂, USNM), 1.viii.1976 (1♀, USNM), Bethseda, G. Steyskal, 12.ix.1981 (1♂, USNM), 14.v.1981 (1♀, USNM), Plummers Isl., at light, 3.viii.1915, R.C. Shannon (1♂, USNM), nr. Plummers Isl., 14.v.1915, R.C. Shannon (1♀, USNM), Montgomery Co., Carderock Park, 18.v.1989, M.J. and R. Molineaux (1♀, USNM), NC: Chatham Co., Haywood, 5.vi.1986, G.C. Steyskal (1♂, USNM), Durham Co., Durham, 17-Acre Wood Preserve, 36°1'27.82"N, 78°55'29.73"W, 8.v.2017, T.S. Feldman, Dichanthelium, em. 4.v.2018, #CSE4482, CNC1135677, CNC1135678 (1♂ 1♀, CNC), Scotland Co., Laurinburg, St. Andrews University, 10.v.2017, T.S. Feldman, Dichanthelium, em. 6–14.v.2018, #CSE4502, CNC1144099, CNC1144100 (1♂ 1♀, CNC), Wake Co., Morrisville, Lake Crabtree County Park, 35°50'37.77"N, 78°47'43.02"W, 6.vi.2018, T.S. Feldman, Dichanthelium scoparium, em. 25.vi.2018, #CSE4695, CNC1135686 (1♂, CNC), NH: White Mts., Stinson Lake, 23.vii.1961, W.W. Wirth (1♀, USNM), NJ: Lakehurst, 1.vi.1962, J.E. Puleston (1♂, USNM), NY: Bear Mt., 30.v.1941, A.L. Melander (1♀, USNM).

USA. NC: Scotland Co., Laurinburg, St. Andrews University, 3.v.2017, T.S. Feldman, Dichanthelium, em. 6.v.2018, #CSE4503, CNC1144101, CNC1144102 (2♀, CNC)

Agromyza parca is currently defined by an evenly dark antenna, minute dorsoapical spinules within the distiphallus and small membranous lateral lobes on the basiphallus. There is a slight amount of variation within the species, possibly indicating the presence of a cryptic taxon. Those specimens with an entirely white calypter (i.e., hairs not brown) have the pale tuft of hairs on the first flagellomere that is no wider than the base of the arista in the males and absent in the female, the eye is 3.5–5.9 × higher than the gena (not 5.2–6.7 × higher) and the distiphallus is usually slightly constricted apically (Fig. 198).

Wing length 2.5–2.7 mm (♂), 3.2–3.4 (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.7. Eye height divided by gena height: 2.5–2.8. First flagellomere slightly longer than high and broadly rounded, without apical tuft of pale hairs. Ocellar triangle relatively small and rounded.

Chaetotaxy : Two ori; two ors. Two well-developed dorsocentrals and one smaller anterior seta. Mid tibia with two posteromedial setae.

Colouration : Body dark brown with halter white, and gena and antenna sometimes slightly paler, with first flagellomere orange on inner-basal 1/3 and tarsi slightly paler. Calypter white with hairs dark brown; hairs sometimes yellowish in females.

Genitalia : (Figs 205–209) Surstylus narrow and rounded, entirely fused to epandrium and with numerous medial tubercle-like setae. Hypandrium with broadly rounded subtriangular apex; inner lobe with membranous base and inner-distal emargination. Postgonite small and lobate. Halves of basiphallus interlocking at base and with inner margins dark; outer margin weakly sclerotised, wide, wing-like and pointed; distal section distinct with long processes flanking distiphallus. Hypophallus lobate with pointed medial process. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); distiphallus with dark enlarged sclerite above insertion of ejaculatory duct; distal section dark and elongate with medial suture and subapical texturing; transverse dorsobasal band produced ventrally. Ejaculatory apodeme with narrow rounded blade with numerous striations, long stem, and stout base.

Unknown – likely Poaceae (Spencer and Steyskal 1986b).

USA: TN, VA*.

Holotype: USA. TN: Hamilton Co., East Ridge, 9.v.1952, G.S. Walley, CNC352947 (1♂, CNC).

USA. VA: Fairfax Co., Turkey Run Park, nr. mouth of Turkey Run, 38°57.9'N, 7°09.4'W, Malaise trap, D.R. Smith, 25.v-6.vi.2006 (1♂ 4♀, USNM), 18–30.v.2007 (3♂, USNM), Turkey Run Park, 0.3 km W mouth Turkey Run, 38°58'N, 77°09.6'W, Malaise trap, D.R. Smith, 17–24.v.2006 (4♂ 1♀, USNM), river, 14–17.v.2006 (4♂ 5♀, USNM), Great Falls Park, quarry, 38°59.1'N, 77°14.8'W, Malaise trap, 18–24.v.2007, D.R. Smith (1♂ 3♀, USNM).

While externally similar to a number of small dark eastern Agromyza, the first flagellomere of A. parilis is entirely dark on the outer face and there is no apical tuft of pale hairs in either sex. The male genitalia are most distinctive, however, and should be examined for confident identification.

Wing length 2.5–3.2 mm (♂), 2.6–2.9 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.7. Eye height divided by gena height: 2.1–3.6. First flagellomere small and rounded with minute tuft of pale apical hairs. Fronto-orbital plate projecting and anterior 1/2 of frons soft and buckled.

Chaetotaxy : Two ori (sometimes three on one side); two ors. Two dorsocentrals, sometimes with very small third seta present anteriorly. Two posteromedial setae on mid tibia.

Colouration : Body mostly dark brown with orange tint, first flagellomere brown with base orange (more extensive on inner surface); frons brownish orange with ocellar triangle, posterior margin and fronto-orbital plate to level of anterior or posterior ors dark brown, sometimes dark laterally along entire margin of eye; lunule yellowish; parafacial beige and gena (excluding ventral margin) light brown; halter white; fore knee and tarsus yellowish. Calypter white with hairs light brown; uncommonly dark brown.

Genitalia : (Figs 210–214) Surstylus visible laterally as small lobe; inner surface with more than a dozen tubercle-like setae. Hypandrium and postgonite as described for A. bispinata. Halves of basiphallus converging to base where both sclerites are fused to each other and phallophorus; with internal fold past midpoint and apices converging as broad triangular lobes. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); base of distiphallus narrow, distal portion broadly rounded, widest subapically and with internal spinulose processes. Ejaculatory apodeme well-developed with central rib visible near base; blade pale.

Poaceae – Echinochloa crus-galli, Panicum miliaceum, Zea mays and probably other cereals (Spencer and Steyskal 1986b).

Canada: BC, ON, QC (Zhu et al. 2004). USA: "Widespread, present in most states” (Frick 1959). Argentina, Cuba, Guadeloupe, Puerto Rico, Dominican Republic, Saint Vincent (Valladares 1998; Martinez and Etienne 2002).

Lectotype: USA. DC [not given]: “Loew coll.”, parvicornis m. (1♂, MCZ).

Canada. BC: Milner, 12.vii.1953, G.J. Spencer, CNC352949 (1♂, CNC), ON: Ottawa, Fletcher Wildlife Gardens, 45°23'7"N, 75°42'11.01"W, 9.vi.2013, O. Lonsdale, CNC1144190 (1♂, CNC), Ottawa, 8.vii.1925, F. Ide, CNC352950 (1♂, CNC), Point Pelee, 8.ix.1954, C.D. Miller, CNC352954, CNC352955 (2♀, CNC), Simcoe, 26.vi.1939, G.E. Shewell, CNC352952 (1♂, CNC), 29.vi.1939, CNC352953 (1♂, CNC), St. Lawrence Is. Nat. Park, Grenadier I. Centre, 26.vi.1975, H.C.W. Walther, Code 1-2406-25, CNC352951 (1♂, CNC), Picton, 10.vii.1970, J.F. McAlpine, CNC353093 (1♂, CNC), QC: Ile de Montreal, 17.vi.1966, Beaulieu, CNC352956 (1♀, CNC). USA. AZ: Sunnyside Canyon, Huachua Mts., 9.vii.1940, D.E. Hardy (1♂, USNM), DE: Wilmington, 31.vii.1951, D.F. Bray (1♂, USNM), Sussex Co., Dewey Beach, 21.xiii.2003, sweeping, K. Bennett (1♂, UDCC), IN: Lafayette 13.[?].1915, J.M. Aldrich (1♀, USNM), MA: Concord, vii.1960, E.H. Wheeler, reared ex. Zea mays (2♂ 3♀, USNM), Franklin Co., Northfield, 276 Old Wendell Rd., 42°38'48.74"N, 72°25'32.15"W, 31.viii.2017, C.S. Eiseman, Zea mays, em. 2–23.vi.2018, #CSE4580, CNC1135703–1135712 (5♂ 5♀, CNC), MD: Montgomery Co., Colesville, Malaise trap, W.W. Wirth, 7.viii.1975 (1♀, USNM), 14.vi.1973 (1♂, USNM), 20.viii.1975 (1♂, USNM), Bethseda, 6.viii.1967, G. Steyskal (1♂, USNM), Colesville, 24.vii.1974, W.W. Wirth (1♂, USNM), 4mi SW of Ashton, Malaise trap, G.F. and J.F. Hevel, 3.ix.1981 (1♂, USNM), 1.ix.1981 (2♂, USNM), NY: L.I. Veg. Res. Fm, Riverhead, at light, 1–7.viii.1938, 30.viii.1938, 7–20.viii.1938, CNC352957, CNC352958, CNC352959, CNC352960, CNC352961, CNC352962, CNC352963, CNC352964, CNC352965, CNC352966, CNC352967, CNC352968 (11♂ 1♀, CNC), TN: Nashville, G.G. Ainslie, Webster No. 9467C (1♂ [with puparium], USNM), VA: Chain Bridge, 14.v.1924, J.R. Malloch (1♀, USNM).

Agromyza parvicornis and A. proxima are highly similar in appearance and develop in some of the same plant genera, and can only be reliably differentiated on the basis of the relative width of the distiphallus and length of the basiphallus. It is possible that A. proxima represents a less common eastern morphological variant of the other, but in the absence of corroborating evidence, these two are maintained here as separate.

Wing length 2.2–2.4 mm (♂), 2.2–2.5 (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.7. Eye height divided by gena height: 2.8–3.4. First flagellomere small and rounded, sometimes with very small tuft of pale hairs apically. Scutum shiny.

Chaetotaxy : Two ori (sometimes three on one side); two ors. Two well-developed dorsocentrals with smaller third seta anteriorly. Hind tibia with two posteromedial setae.

Colouration : As described for A. parvicornis, except fronto-orbital plate usually brownish orange around base of all fronto-orbital setae.

Genitalia : (Fig. 215) Genitalia as described for A. parvicornis except as follows: basiphallus short, only slightly longer than distiphallus; distal section of distiphallus narrow, with sides only slightly bulging subapically.

Variation : MD male from Anne Arundel Co. with distal 2/5 of first flagellomere covered with pale hairs; genitalia as described above, but surstylus relatively small and spherical; distal 2/3 of first flagellomere dark and pedicel orange distally; frons dark brown. VA female with relatively large ovate distoventral patch of pale hairs on first flagellomere; body entirely dark with pedicel slightly paler, calypter entirely white, notopleuron and postpronotum reddish, and wing veins whitish on basal 1/2. The female is only tentatively allied with the MD male on the basis of similar dark colouration and the increased size of the pale haired patch on the first flagellomere.

Poaceae – Dichanthelium sp, Echinochloa walteri, Panicum dichotomiflorum (Scheffer and Lonsdale 2018, Spencer and Steyskal 1986b).

Canada: MB. USA: DE*, FL, MA*, MD*, NY, VA(?).

Holotype: USA. FL: Sweetwater, Tamiami Canal (1♂, USNM).

Paratypes: Canada. MB: 2 mi N Forrest, Populus balsamifera stand around slough, 19.vii.1958, J.G. Chillcott, CNC352969 (1♂ [head missing], CNC). USA. FL: Sweetwater, 3.viii.1963, ex. Echinochloa walteri, leg. 23.vii.1963, K.A. Spencer (1♂ 1♀ [same pin, with puparia], USNM).

USA. DE: Newark, 30.vii.1974 (1♂, UDCC), Stanton, 8.viii.1951, D.F. Bray (1♂, USNM), MA: Greenfield, 6.[?].1914, A.L. Melander (1♂, USNM), Wayland, 28.[?], J.J. Pratt, LT (1♂, USNM), MD: Bethseda, 12.ix.1981, G.C. Steyskal (1♀, USNM), Colesville, 15.viii.1975, Malaise trap, W.W. Wirth (1♂, USNM), Anne Arundel Co., nr. Edgewater, Smithsonian Envir. Res. Centre, 38°53'N, 76°33'W, 10.vii.1993, G.F. Hevel (1♂, USNM), VA: Sherando Lake, 10 mi SW Waynesboro, 25.vi.1970, L.V. Knutson (1♀, USNM).

Wing length 2.4–2.6 mm (♂), 2.0–2.6 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.7–0.9. Eye height divided by gena height: 4.8–4.9. First flagellomere small and ovate with small tuft of apical hairs in male. Ocellar triangle small and rounded (smaller in holotype). Scutum shiny.

Chaetotaxy : Two ori (sometimes three on one side); two ors. Three dorsocentral setae with anterior seta reduced. Mid tibia with two posteromedial setae.

Colouration : Body dark brown with orange tint; first flagellomere dark brown with faint orange tint towards base sometimes evident; lunule paler; parafacial sometimes with orange tint; halter white; tarsi and base of fore tibia yellow. Wing veins light brown. Calypter white with hairs usually brown (white in some females).

Genitalia : (Figs 216–220) Genitalia largely as described for A. parvicornis, except as follows: basiphallus long and well-sclerotised, halves overlapping at base, weakened point present past midpoint and apex split with dark ventral branch; distiphallus narrow, with broad medial constriction and with elongate ventral sulcus below distomedial ridge; ejaculatory apodeme small with blade pale.

Poaceae – Dichanthelium spp. (Eiseman and Lonsdale 2018, 2019).

Canada: ON*. USA: AR, CT*, DC*, GA, MA, MD*, MN, NC, OH, OK, NY*, SC*, VA*.

Holotype: USA. AR: Garland Co., Hot Springs, 15.v.1979 (1♂, USNM).

USA. GA: Rabun Co., Rabun Bald, 1280 m, 16.vii.1957, J.G. Chillcott, CNC352972 (1♀, CNC), Rabun Bald, 914 m, 14.vii.1957, J.G. Chillcott, CNC352971 (1♂, CNC), NC: Pisgah Forest, Looking Glass Pk., 19.vii.1957, “K.A. Spencer, col.”, W.R. Richards, CNC352970 (1♂, CNC).

Canada. ON: Algonquin Pk., 45°50'0"N, 77°38'0"W, 19.vii.1991, J.R. Vockeroth, CNC353094 (1♂, CNC), Metcalfe, 2mi N, 15.v.1982, B.E. Cooper, CNC353095 (1♂, CNC), 10.vi.1982, CNC353097 (1♂, CNC), 25.v.1982, CNC353096 (1♂, CNC), Ottawa, damp second-growth forest in Acer-Betula wood, 27.vi.1989, J.R. Vockeroth, CNC353098 (1♂, CNC). USA. CT: Waterton, 5.vi.1931, A.L. Melander (1♀, USNM), Putnam Park, A.L. Melander, 18.vii.1939 (1♂, USNM), 20.vii.1939 (1♂, USNM), 24.vii.1939 (1♀, USNM), Redding, A.L. Melander, 26.vi.1929 (1♂, USNM), 1.vi.1929 (1♀, USNM), 10.vi.1929 (1♀, USNM), 8.vi.1930 (1♂ 2♀, USNM), 11.vi.1929 (1♀, USNM), 27.vii.1938 (1♀, USNM), DC: 11.vi.1926, J.M. Aldrich (2♂, USNM), Chain Bridge, 8.v.1928, J.M. Aldrich (1♂, USNM), Washington, 17.viii.1913, A.L. Melander (2♂, USNM), MA: Concord, 17.vi.1961, W.W. Wirth (1♂, USNM), Franklin Co., Northfield, 276 Old Wendell Rd., 4.vii.2016, C.S. Eiseman, Dichanthelium acuminatum ssp. fasciculatum, em. 21.vii.2016, #CSE2787, CNC654200–654202 (1♂ 2♀, CNC), MD: Bethseda, 30.v.1980, G.C. Steyskal (1♀, USNM), Plummers Isl., 3.vi.1914, R.C. Shannon (1♂, USNM), Montgomery Co., 4mi S of Ashton, 24.vii.1982, G.F. and J.F. Hevel (2♀, USNM), NC: Scotland Co., Laurinburg, St. Andrews University, 18.v.2016, T.S. Feldman, Dichanthelium em. 13.vi.2016 , #CSE2572, CNC634813–634815 (3♂, CNC), Durham Co., Durham, 17-acre Wood Preserve, 15.v.2016, T.S. Feldman, Dichanthelium clandestinum, em. 4.vi.2016, #CSE2542, CNC654303–654306 (4♂, CNC), Scotland Co., Laurinburg, St. Andrews University, 11.v.2016, T.S. Feldman, Dichanthelium scoparium, em. 3.vi.2016, #CSE2540, CNC653948, CNC653949 (1♂ 1♀, CNC), NY: Lk. George, 26.vii.1929, A.L. Melander (1♀, USNM), Yonkers, 3.vi.1927, A.L. Melander (1♀, USNM), 5.vi.1927 (1♀, USNM), Peekskill, 11.vi.1927, A.L. Melander (1♂, USNM), Bear Mt., 31.v.1941, A.L. Melander (1♂, USNM), OH: Hocking Co., South Bloomingville, Deep Woods Farm, 5.viii.2016, C.S. Eiseman, Dichanthelium clandestinum, em. 20–22.viii.2016, #CSE2925, CNC654480–654482 (1♂ 2♀, CNC), SC: Beaufort Co., Fripp Island, 26.ix.1973, G.C. Steyskal (1♂, USNM), Highland Fall, 6.vii.1941, A.L. Melander (1♀, USNM), Cobleskill, 11.viii.1970, L. Knutson (1♀, USNM), VA: Glencarlyn, 23.v.1925, J.R. Malloch (1♂, USNM), Falls Church, Holmes Run, 24.viii.1960, light trap, W.W. Wirth (1♀, USNM), Rosslyn, 25.vi.1913, R.C. Shannon (1♀, USNM), Fairfax Co., Great Falls Park, swamp trail, 38°59.4'N, 77°15.2'W, Malaise trap, trap #1, 3–7.v.2007, D.R. Smith (1♂, USNM).

Agromyza pudica is recorded here in Canada, D.C., and five states for the first time.

(from Eiseman and Lonsdale 2018). Wing length 2.3–2.5 mm (♂), 2.3–3.0 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.7. Eye height divided by gena height: 6.9–9.2. Ocellar triangle relatively small and rounded. First flagellomere small and nearly circular or slightly longer than high, with nearly indistinct apical tuft of pale hairs. Notum pruinose.

Chaetotaxy : Two or three ori (anterior seta small if present); two ors. Ocellar and postvertical setae subequal to outer vertical seta. Five dorsocentrals, strongly decreasing in length anteriorly. Eight irregular rows of acrostichal setulae. Mid tibia with one (male paratype) or two posteromedial setae.

Colouration : Setae dark brown with light brown reflection. Body predominantly dark brown (female darker) with light pruinosity; antenna dirty orange with distal 1/2 of first flagellomere infuscated (more so dorsally) in holotype, entirely brown in paratypes, with antenna entirely dark brown in female; frontal vitta, gena and postgena paler; apices of fore or all femora narrowly yellow; tarsi yellow; fore tibia light brown, fading to yellow at base. Calypter white with hairs brown. Halter white.

Genitalia : (Figs 221–224) Surstylus not distinct from epandrium, barely visible laterally, flat on inner surface and with four large spines. Cerci narrow and convergent. Hypandrium broad with thick arch, small apical process, and large inner lobe with two distal setae and several minute basal pits. Postgonite lobate and downturned. Proepiphallus and metepiphallus strongly reduced, flattened. Phallophorus elongate on left side. Halves of basiphallus strongly diverging from, and partially fused to phallophorus; lateromedially with lightly sclerotised membranous lobe; apex folded inwards, with pointed basal process and elongate distal process that is fused to mesophallus. Hypophallus broad, flat, and heavily sclerotised; apically split in dissected NC male. Mesophallus cylindrical, dark, basally rounded, slightly longer than wide, fused to distiphallus. Distiphallus broad, black, ventrally tilted and cup-like with constricted opening enclosing haired inner process. Ejaculatory apodeme well-developed with blade paler, no medial rib evident.

Fabaceae – Robinia pseudoacacia, Wisteria floribunda.

USA: CT, NC, VA.

Holotype: USA. VA: nr. Plummers Isl., 20.v.1914, R.C. Shannon (1♂, USNM).

Paratypes: USA. CT: Hartford Co., East Hartford, Two Rivers Magnet Middle School, 4.vi.2016, em. 27–29.iv.2017, C.S. Eiseman, ex Robinia pseudoacacia, #CSE3574, CNC939943–939946 (3♂ 1♀, CNC), NC: Scotland Co., Laurinburg, St. Andrews University, 24.iv.2015, em. 16–18.iii.2016, T.S. Feldman, ex Robinia pseudoacacia, #CSE2248, CNC653954, CNC653955 (1♂ 1♀, CNC), 10.iv.2017, Robinia pseudoacacia, em. 22.iv.2018, #CSE4423, CNC1135665 (1♂, CNC), 4.iv.2016, em. 18.iv– 3.v.2017, T.S. Feldman, ex Wisteria floribunda, #CSE3518, CNC939744–939747 (1♂ 3♀, CNC).

(Fig. 225). Externally as described for A. bispinata except as follows: Wing length 2.3–3.3 mm (♂). Length of ultimate section of vein M4 divided by penultimate section: 0.5–0.8. Eye height divided by gena height: 2.7–4.8. Small additional ori present in male with five spines on surstylus. First flagellomere sometimes paler with orange tint or predominantly orange with distal 1/2 infuscated; always enlarged in male. Postpronotum sometimes light brown or with orange tint. Wing veins brown to yellow. Fore tibia of MD male yellow with centre brownish.

Genitalia : (Figs 226–231) Surstylus fused to epandrium, easily viewed laterally, with dark anterior lobe and dark pronounced protuberances at base of marginal spines (three to five in number). Hypandrium, postgonite and ejaculatory apodeme as described for A. bispinata. Left sclerite of basiphallus overlapping base of right sclerite, which is fused to phallophorus; both halves with lateromedial membranous projection, and with weak connection to incurved distal section. Distiphallus of “nigripes-type” (capsule-shaped with subbasal opening for entry of ejaculatory duct, pronounced dorsobasal collar, and medial convolution); ventral curve with truncated sclerotised elbow; distal section with bulging, internally spinulose medial section.

Variation : Dissected paratype with two spines on surstylus (as in A. bispinata), but surstylus and remaining genitalia otherwise identical to holotype.

Variation : female paratypes: Wing length 2.9–3.1 mm. Length of ultimate section of vein M4 divided by penultimate section: 0.4. Eye height divided by gena height: 8.7–11.8. First flagellomere smaller, ovate; base always orange, reminder orange to brown. Anterior 1/2 of frons sometimes orangish.

Unknown – likely Poaceae (Spencer and Steyskal 1986b).

Canada: AB*, MB[?], NB*, ON, QC. USA: MD*, MO, NH*, NY*, UT*, VA*.

Holotype: Canada. ON: Ottawa, 17.vi.1946, G.E. Shewell, CNC352973 (1♂, CNC).

Paratypes: Canada. MB: Int. Peace Gardens, Turtle Mtn. For. Res., 7.viii.1958, J.G. Chillcott, CNC Type No. 10355, CNC352975 (1♀, CNC), ON: Ottawa, 15.vii.1957, J.E.H. Martin, CNC Type No. 10355, CNC352977 (1♀, CNC), 20.vi.1957, J.G. Chillcott, CNC Type No. 10355, CNC352974 (1♂, CNC), QC: Hull, 5.vi.1959, J.R. Vockeroth, CNC Type No. 10355, CNC352976 (1♀, CNC), Old Chelsea, summit of King Mt., 350 m, 11.vi.1959, J.R. Vockeroth, CNC Type No. 10355, CNC352978 (1♀, CNC).

Canada. AB: Elkwater L., 21.vii.1956, O. Peck, CNC353101 (1♂, CNC), NB: Kouchibouguac N.P., 11.vii.1977, J.F. McAlpine, Code-6035C, CNC352990–352992 (3♂, CNC), 12.vii.1977, J.F. McAlpine, Code-6040H, CNC352989 (1♂, CNC), 13.vii.1977, G.A. Calderwood, Code-5599I, CNC352993 (1♂, CNC), 30.vi.1977, J.R. Vockeroth, Code-5456V, CNC352986, CNC352987, CNC352981–352985 (7♂, CNC), 6.vii.1977, G.A. Calderwood, Code-54900, CNC352988 (1♂, CNC), 9.vii.1977, J.F. McAlpine, Code 6024R, Code-6024R, CNC352979, CNC352980 (2♂, CNC), ON: Ottawa, on leaf of Philadelphus coronarius, 13.vii.1959, J.R. Vockeroth, CNC353100 (1♂, CNC). USA. MD: Plummers Isl., 14.vi.1913, R.C. Shannon (1♂, USNM), NH: Jefferson Notch, 30.vii.1961, creek margin, W.W. Wirth (1♂, USNM), NY: Bear Mt., 31.v.1941, A.L. Melander (1♂, USNM), UT: Cache Co., Green Canyon, 23.vii.1964, Malaise trap, W.J. Hanson (1♂, USNM), VA: Shenandoah, Big Meadows, 3.vii.1939, A.L. Melander (1♂, USNM), Fairfax Co., Dead Run, 9.vi.1915, R.C. Shannon (1♂, USNM).

See comments for Agromyza bispinata. The female paratypes of A. tacita cannot be confidently assigned to this species, which is mostly defined by male genitalic characters, and their placement should be re-evaluated when the boundaries of species in the A. bispinata complex can be better delimited.

Wing length 1.7–2.2 mm (♂), 1.8–2.3 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.9–1.0. Eye height divided by gena height: 3.5–10.0. Arista pubescent. First flagellomere small and rounded, without pale tuft of hairs. Fronto-orbital plate slightly projecting (more so anteriorly). Ocellar triangle small and rounded.

Chaetotaxy : Two ori; two ors. Orbital setulae in one row. Ocellar and postvertical setae subequal to fronto-orbitals. Two strong dorsocentral setae, with second seta ~ ¾ length of first seta; much weaker third dorsocentral not much larger than acrostichal seta. Acrostichal seta ~ 2 × length of setulae. Acrostichal setulae in 8 scattered rows, tapering posteriorly to level of first dorsocentral. Mid tibiae without posteromedial setae.

Colouration : Setae dark brown. Antenna yellow to orange; first flagellomere darker orange with basal margin paler and with small brown curved spot around base of arista posteriorly and along outer surface. Frons yellow with posterolateral corner and posterior margin dark brown; orbital plate darker, brownish orange behind anterior ors, becoming darker posteriorly, and with narrow brownish line continuing anteriorly along eye margin beside ori; ocellar spot rounded, dark brown, slightly larger than tubercle; remaining posterior 1/2 or less of frontal vitta brownish orange, becoming darker posteriorly, sometimes with this dark region restricted to large circle around ocellar spot. Lunule light yellow. Gena yellow with ventral brownish line. Parafacial yellow. Face whitish yellow. Mouthparts yellow; clypeus with brown tint that is darker laterally. Postgena, back of head and remainder of body mostly dark brown; body subshiny. Apex of fore femur yellowish orange for length equal to width of femur apex; apex of mid femur narrowly paler brown apically; tibiae sometimes paler brown with base and apex yellowish, and mid tibia sometimes with yellow mottling medially; tarsi yellow, becoming more brown tinted on posterior legs; wing veins brown; halter yellow with orange-brown tint on stem; calypter margin and hairs brown.

Variation : Posterior 1/2 of frons brownish in holotype and FL specimen. IL male with first flagellomere entirely light yellow, head brighter and scutum shiny.

Genitalia : (Figs 236–242) Epandrium as long as high; fused to small, inwardly directed surstylus. Cercus large, well-developed, venter of inner surface covered with tubercle-like setae. Hypandrium with large apical apodeme and narrow basal arms; medially with weakly sclerotised region connected to L-shaped inner lobe bearing row of minute setae. Postgonite in lateral view with short, flat globose body with extremely long tail; inner surface with apically setose shelf. Phallophorus elongate cylindrical, apicodorsal margin irregularly sclerotised to base of basiphallus. Basiphallus with small left basolateral plate partially fused to large dorsal plate that is strongly curved ventrally at base and with medial and apical lobes that wrap along right lateral surface of shaft. Ejaculatory duct widening to mesophallus, which is round, bulbous, and clear with thick triangular sclerotisation ventrally. Distiphallus composed of one pair of upturned “wings” that nearly meet ventrally and are very narrowly connected dorsally; each wing with small, dark, smooth base expanding into densely haired, distally pointed lobes. Ejaculatory apodeme weakly sclerotised, with broad slanted base and short stem grading into thick blade with faint apical striations; sperm pump with slight basal sclerotisation.

Cannabaceae – Celtis laevigata. Possibly Ulmus Americana (Ulmaceae) (Eiseman 2021).

Canada: ON, QC. USA: AK, DC, FL, IA, IL, KS, MS, NY, PA, TX, VA*.

Holotype: USA. DC: “District of Columbia” (1♀, USNM).

USA. FL: Hialeah, em. 10.v.1963, mine Celtis laevigata, 22.ix.1963 (1♂ 1♀ [same pin, with puparia]), Gainesville, Newman’s Lake, 26.iv.1952, O. Peck, CNC352994 (1♂, CNC), Hialeah, 22.ix.1963, mine Celtis laevigata, Em. 5.x.1963, [K.A. Spencer], CNC352996 (1♂ 1♀ [with puparia], CNC), IL: [illegible], 15.v.1919 (1♀, USNM), NY: Suffolk Co., Stony Brook Village, larva coll. 19.vi.1993, S.J. Scheffer, 93-187 (1♂[illustrated], USNM) , eclosed 9.vii.1993 (1♂, USNM), eclosed 8.vii.1993 (1♀, USNM), eclosed 10.vii.1993 (3♂, USNM), eclosed 11.vii.1993 (1♀, USNM), elcosed 17.vii.1993 (1♂, USNM), TX: Kerrville, 4.iv.1959, J.F. McAlpine, CNC352995 (1♂, CNC), Welder Wildlife Ref. nr Sinton, 19–23.iii.1965, J.G. Chillcott, CNC352997 (1♀, CNC), VA: Fairfax Co., Turkey Run Park, nr. mouth of Turkey Run, 38°57.9'N, 7°09.4'W, Malaise trap, 26.iv-2.v.2007, D.R. Smith (3♀, USNM), Turkey Run Park, 0.3 km W mouth Turkey Run, 38°58'N, 77°09.6'W, Malaise trap, D.R. Smith, 18–30.v.2007 (1♀, USNM), 29.iii-25.iv.2007 (1♂, USNM), Great Falls Park, quarry, 38°59.1'N, 77°14.8'W, Malaise trap, D.R. Smith, 24.iv-2.v.2007 (3♂ 1♀, USNM), 10–17.v.2007 (1♂, USNM), 3–10.v.2007 (1♂, USNM).

This species is clearly allied to Agromyza aristata, being similar in external and male genitalic morphology. The anterior portion of the head is mostly pale, the cercus is covered with small tubercle-like setae along the anterior surface, and the mesophallus is a ventral band separate from a curved, plate-like distiphallus. The most immediate difference in the genitalia is the densely haired distiphallus and short mesophallus, but the hypophallus has an apical apodeme, the basiphallus is also strongly curved and irregular in outline, the postgonite broadly lobate (lateral view) and the ejaculatory apodeme is well-developed. Externally, the pale portions of A. aristata are light yellow, not orange to yellowish, and the legs are extensively yellow.

Wing length 3.2 mm. Length of ultimate section of vein M4 divided by penultimate section: 0.6. Eye height divided by gena height: 3.4. First flagellomere longer than wide with rounded apex; apical margin possibly with longer, paler hairs. Fronto-orbital plate and parafacial slightly projecting. Ocellar triangle broadly rounded and short, not extending much past ocelli. Buccal cavity subquadrate.

Chaetotaxy : Four ori; one ors (not two as reported by previous authors). Four postsutural dorsocentrals, decreasing in length anteriorly. Mid tibia with two posteromedial setae.

Colouration : Body predominantly brown with halter white. Gena (excluding ventral margin), parafacial and frons (excluding posterolateral corner, posterior margin and ocellar triangle) light brownish orange, with fronto-orbital plate lightly pigmented posteriorly to base of posterior ori. First flagellomere, scape and pedicel orange, sometimes with dark spot at base of arista. Lunule orange. Face brown. Palpus and clypeus dark brown. Calypter margin and hairs white. Legs dark brown with knees yellow and tibiae and tarsi with orange tint (brighter on tarsi).

Genitalia : (Fig. 151) Surstylus triangular with basal suture obliterated; with minute apical setae and medial tubercle-like setae. Hypandrium relatively long and narrow with minute apical point. Postgonite very broad, flat, and lobate. Halves of basiphallus long with ventral margin weakly defined, apices hooked, and right sclerite with broader base. Distiphallus very long, cylindrical, dark and with distal 2/5 bifid and not strongly curved. Ejaculatory apodeme small and thin, without apical blade.

Variation : Canadian material differs as follows: wing length 3.0–3.2 mm (♂), 3.4–3.8 mm (♀); eye height divided by gena height 5.1–10.6; first flagellomere with relatively discrete ovate pilose patch; 2 ors and 2–3 ori; first flagellomere brownish on distal and dorsal margins anterior to arista base; posterior 1/3 of frons much darker; fronto-orbital plate with ill-defined brown margin along length; parafacial dark brown; distiphallus only split on distal 1/10.

Unknown – adult collected on Phyllocarpus (Fabaceae).

Canada: ON*. USA: VA.

Holotype: USA. VA: Great Falls, vi.1922, Banks (1♂, MCZ).

Canada. ON: Orleans, Chapel Hill, at flowers of Phyllocarpus, 23.vi.1994, J.R. Vockeroth, CNC353052 (1♀, CNC), Ottawa, Damp second-growth Acer-Betula woods, 12.vii.1994, J.R. Vockeroth, CNC353053 (1♀, CNC), 15.vi.1998, CNC353059 (1♀, CNC), 16.viii.1992, CNC353046 (1♂, CNC), 17.vi.2003, CNC353056 (1♀, CNC), 2.vii.1993, CNC353044 (1♂, CNC), 24.vii.2000, CNC353049 (1♂, CNC), 29.vi.1994, CNC353058 (1♀, CNC), 29.vi.1997, CNC353047 (1♂, CNC), 29.vii.1992, CNC353045 (1♂, CNC), 30.vi.1991, CNC353054 (1♀, CNC), 30.vii.1993, CNC353051 (1♀, CNC), 6.viii.1993, CNC353043, CNC353057 (1♂,1♀, CNC), 7.viii.1993, CNC353050 (1♂, CNC), 7.viii.2000, CNC353055 (1♀, CNC), 9.vii.2000, CNC353048 (1♂, CNC).

The Canadian material varies slightly from the holotype, being more similar in external appearance to Agromyza ambrosivora, although the straight (not strongly curled) distiphallus would seem to preclude this option, and the anterior margin of the buccal cavity is relatively straight (more pointed in A. ambrosivora). The phallus of these Canadian specimens further differs from the holotype in that only the apex of the distiphallus is cleft, but these external and phallic differences will be tentatively treated as within-species variation until additional specimens can be measured.

The phallus is similar to that of a Nearctic and European leaf miner on Urtica (Urticaceae), Agromyza reptans (Spencer and Steyskal 1986b: figs 395, 396). The distiphallus of both is straight and apically split, but that of A. reptans is much shorter, paler, and with the apical split represented by one pair of separate, darker cylindrical arms (not the ends of a single, continuous, narrow tube), barely longer than wide and stouter than the base.

Externally as described for A. isolata except as follows: Wing length 2.4–2.7 mm (♂), 2.4 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.8. Eye height divided by gena height: 3.8–6.5. Sometimes three ori on one side of frons. Overall colour slightly darker, with antenna dark brown and calypter margin and hairs always brown; mid and hind tibiae brown with apex and sometimes base yellowish. First flagellomere sometimes appearing slightly angulate and with some longer apical hairs.

Genitalia : (Figs 243–249) Surstylus not distinct from epandrium (which has desclerotised distal emargination), and with several setae and tubercle-like setae on inner margin. Hypandrium long and narrow, sides nearly parallel and with tapered apical process. Postgonite small, dome-like with several outer setulae. Phallophorus atrophied on right side, produced and slightly setulose on left side, fused to right sclerite of basiphallus, twisting around shaft; left sclerite of basiphallus narrow, curving around venter at base. Basiphallus broad and fringed basally with dextral twist. Hypophallus composed of weak, long narrow band. Mesophallus short, cylindrical, with longer ventral plate. Distiphallus short, subcylindrical with ventral break, and fringed along distal and ventral margins.

Rosaceae – Rubus.

Canada: AB, BC, ON, NS. USA: CT*, DC*, MA, MD*, NC, NH*, NY*, PA*, TN, VA*.

Holotype: Canada. NS: Shelburne, 10.viii.1958, J.R. Vockeroth, Type No. 10356, CNC352998 (1♂, CNC).

ON: Maynooth, 22.vi.1953, J.F. McAlpine, CNC353000 (1♂, CNC), Ottawa, 5.vi.1946, G.E. Shewell, CNC353001, CNC353002 (2♂, CNC), Golden Lake, 3.ix.1956, J.R. Vockeroth, CNC353003 (1♀, CNC), QC: Old Chelsea, 18.viii.1961, J.R. Vockeroth, CNC352999 (1♂, CNC).

Canada. BC: 20 km E Pemberton, 14.viii.1991, A. Borkent, CNC353014, CNC353015 (2♂, CNC), Hagensborg, 12.vii.1992, A. Borkent, CNC353016 (1♂, CNC), 42 km NE Hope, 2.viii.1991, A. Borkent, CNC353015 (1♂, CNC), 32 mi SW of Terrace, 9.vii.1960, J.G. Chillcott, CNC353017 (1♂, CNC), ON: St. Lawrence Is. Nat. Park, Aubrey Island, 4.ix.1976, W. Reid, Code 4618-R, CNC353006 (1♂, CNC), St. Lawrence Is. Nat. Park, Cedar Island, 31.viii.1976, W. Reid, Code 4586-L, CNC353007 (1♀, CNC), St. Lawrence Is. Nat. Park, McDonald Is., 14.vi.1976, 6.ix.1976, A. Carter, W. Reid, Code 4092-J, Code 4633-G, CNC353005, CNC353008 (1♂ 1♀, CNC), St. Lawrence Is. Nat. Park, Thwartway Is., 24.vii.1976, W. Reid, Code 4198-L, CNC353009 (1♀, CNC). USA. CT: Kent Fall, 28.viii.1940, A.L. Melander (1♂, USNM), Redding, 28.v.1939, A.L. Melander (1♂, USNM), DC: Washington, “v-17”, J.M. Aldrich (1?, USNM), MA: Franklin Co., Northfield, Crag Mountain, 11.x.2013, ex. Rubus (blackberry), em. 27.iii.2014, C.S. Eiseman, #CSE1030, CNC384794 (1♂, CNC), MD: Glen Echo, 21.viii.1921, J.R. Malloch (1♂, USNM), Colesville, 1.v.1977, W.W. Wirth (1♀, USNM), Montgomery Co., Dickerson, 14.vii.1974, G.A. Foster (1♀, USNM), NC: Highlands, Wilson’s Gap, 944 m, 12.v.1957, J.R. Vockeroth, CNC353011 (1♀, CNC), Mitchell Co., Roan Mtn, 1889 m, 13.viii.1957, J.G. Chillcott, CNC353010 (1♀, CNC), Wyah Bald, 13.vi.1957, C.J. Durden, CNC353012 (1♀, CNC), NH: White Mts., Stinson Lake, 23.vii.1961, W.W. Wirth (1♂, USNM), NY: Allegany St. Pk., 28.v-3.vi.1963, stream margin, W.W. Wirth (1♂, USNM), Orleans Co., Albion, 11.vi.1963, Burma woods, W.W. Wirth (1♂, USNM), Monroe Co., Braddock Bay, 12.vi.1963, near marsh, W.W. Wirth (1♂, USNM), PA: Mineral Spr., 5.ix.1927, A.L. Melander (2♂, USNM), Monroe Co., Mt. Pocono, 28.vii.1985, G.F. and J.F. Hevel (1♂, USNM), TN: Smokies, Chimneys, A.L. Melander, 25.vi.1941 (1♀, USNM), 20.vi.1941 (1♂, USNM), Indian Gap to Clingman’s Dome, 5200–6600', 6.viii.1957, J.G. Chillcott, CNC353004 (1♂, CNC), VA: Luray, 24.vi.1923, A.L. Melander (1♂, USNM), Fairfax Co., Turkey Run Park, nr. mouth of Turkey Run, 38°57.9'N, 7°09.4'W, Malaise trap, river trap, 17–24.v.2006, D.R. Smith (1♀, USNM).

Euhexomyza was described by Lonsdale (2014) for a lineage of mostly north-temperate Salicaceae-feeding species where the larva forms an ovate gall in the cortex of a twig. These species were previously treated as part of Hexomyza Enderlein, but Lonsdale (2014) found the genus to be a polyphyletic dumping ground for a miscellany of gall-forming species, with the morphologically disparate type species belonging to Ophiomyia. He subsequently included the name Hexomyza as a junior synonym of Ophiomyia.

Species are brown and non-metallic (Fig. 44), they have a rounded clypeus and lack a prescutellar acrostichal. The fronto-orbital plate and parafacial are pronounced, forming a strong ring around the eye, the postsutural intra-alars are subequal (anterior seta never strong), and only the mid tibia sometimes has a lateromedial seta. The male genitalia (at least of the north temperate Salicaceae-feeders) are typified by a distiphallus that has the base broad and rounded and the apex tapered, and the phallophorus has a unique ventral “pouch” emerging from the distal margin (Fig. 250; Lonsdale 2014: fig. 62).

(Figs 47, 48). Wing length 1.9 mm (♂♀). Length of ultimate section of vein M4 divided by penultimate section: 1.2. Eye height divided by gena height: 8.6. Ocellar triangle large, glossy outside of tubercle and sharply pointed anteriorly. First flagellomere broadly rounded. Clypeus broadly rounded anteriorly. Distance between crossveins as long as dm-m. Costa not extending much past R₄₊₅. Lunule broad, very shallow. Base of antennae broadly separated. Face flat. Fronto-orbital plate narrow.

Chaetotaxy : One strongly incurved ori; three ors; setae decreasing in width and length anteriorly. Ocellar and postocellar setae well-developed. Orbital setulae reclinate. Two well-developed dorsocentrals. Acrostichal setulae in eight rows. Posteromedial tibial setae absent.

Colouration : Calypter and wing entirely white with veins brownish (costa darker). Halter brown. Body entirely brown to dark brown with gena and centre of frons paler.

Genitalia : Unknown.

Unknown – likely Salix (Salicaceae).

Canada: ON. USA: MD. Gall attributed to this species observed in AB (Spencer, 1969).

Holotype [winnemanae]: USA. MD: Plummers Island, 27.vi.1909, W.L. McAtee (1♀, USNM).

Holotype [albicula]: Canada. ON: Ottawa, 7.iv.1948, ex. gall on Salix sp., G.E. Shewell (1♂, CNC).

Paratype [albicula]: Canada. ON: Dryden, 12–13.vi.1960, Kelton and Whitney (1♀, CNC).

Euhexomyza albicula (Spencer) stat. reinst., comb. nov. (Figs 45, 46, 250) was included as a junior synonym of H. winnemanae by Spencer and Steyskal (1986b), but following examination of the types of both species, both are recognised here as distinct, and the former is resurrected from synonymy. Aside from having white wings and a similar body size, the two species are strikingly dissimilar. Euhexomyza albicula differs as follows: eye height divided by gena height 2.0–2.1; eye relatively small and broadly surrounded by fronto-orbital plate, parafacial and occiput when seen laterally; fronto-orbital plate broad and bulging (more so medially); two ors, two ori (not much longer than ocellar seta); ocellar triangle broad, rounded apically and subshiny; first flagellomere smaller, ovate and with longer hairs; lunule semi-circular and bulging; clypeus broader medially; ocellar and postocellar setae not much longer than ocellar tubercle; scutellum with second small pair of distolateral scutellar setae well-developed and with additional seta on left side in female; veins white, excluding costa, subcosta and base of Rs; calypter margin and hairs brown; body subshiny and light brown to brown (not dark brown).

One additional pair of lateral scutellar setae is also present in the northeastern North American species Euhexomyza salicis (Malloch), which has the costa extending to vein M₁₊₂ (not R₄₊₅).

Japanagromyza is species-poor in North America north of Florida, but the species J. viridula (Coquillett) is relatively abundant from the east coast to Alberta, Kansas and Arizona, and the unusual J. rutiliceps (Melander) is known from Montana to California. The genus, which was redefined in Lonsdale (2013), has one pair of acrostichal setae and/or a lateromedial seta on the mid tibia. Agromyza also has developed acrostichal setae, but it differs in having a stridulatory file. Those Japanagromyza without acrostichals are superficially similar to Melanagromyza, but species in the latter genus have a longer ocellar triangle, more pronounced fronto-orbital plates, and often dorsally setose eyes.

The majority of species occurring in the New World can be characterised as follows: colour black (or with iridescence); only two pairs of widely spaced dorsocentrals; knob of halter white (base of knob and stem sometimes variably brown, and occasionally entirely dark, as in J. brooksi Spencer from Ontario); fore tibia with lateromedial seta (absent in J. brooksi and a number of non-Nearctic species); surstylus often long and narrow; male cercus very large and often bearing large tubercle-like setae (similar structures are found in some Agromyza); hypandrium with long, narrow, ventrally curving apodeme apically; phallus long, narrow and clear (morphology much more varied globally), and with ejaculatory apodeme sometimes very thin or atrophied. The unusual J. rutiliceps (Melander) from the western United States differs in most of these features, and its placement is uncertain.

(Figs 49–51). Wing length 2.7–3.2 mm (♂), 3.1–3.2 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6–0.7. Eye height divided by gena height: 8.0–8.3. Ocellar triangle faintly outlined. Fronto-orbital plate and ocellar tubercle subshiny. Lunule height 1/2 width, silvery pruinose; lunule and face broad and well-sclerotised with face flat. Clypeus broadly rounded. Notum and head with light dusting of pruinosity. Arista virtually bare.

Chaetotaxy : All setae well-developed and setulae short and sparse. Two ori; two ors (widely separated). Two postsutural dorsocentrals. Ten rows of acrostichal setulae; acrostichal setula present. Postocellar and ocellar setae well-developed. Fore tibia with one lateral seta; mid tibia with two posteromedial setae.

Colouration : Setae black (setulae on ocellar tubercle sometimes golden-brown). Body predominantly dark brown; thorax (less so on pleuron) and abdomen with metallic green reflection, and epandrium faintly to distinctly reddish brown. Wing veins brown. Calypter and halter white.

Genitalia : (Figs 251–256) Surstylus fused to epandrium; suture obliterated; very narrow, apex rounded, nearly as high as epandrium; inner surface with patches of numerous tubercle-like setae distally and basally; twisted, inner face visible posteriorly. Hypandrium large, elongate with very long, stout, apical process; inner lobe bare, narrow and transverse. Postgonite broad, ovate, flat, and bare. Phallophorus small, fused to basiphallus. Basiphallus a single plate dorsal to right lateral. Hypophallus slightly shorter than basiphallus, dark, linear. Distiphallus very long, pale, and relatively straight, composed of longer flagellum on left side and shorter flagellum on right side, connected by thin membrane; often longer than illustrated. Mesophallus indistinct. Ejaculatory apodeme narrow, blade reduced with very shallow basolateral process; sperm pump unsclerotised with minutely spinulose ventral surface.

Fagaceae – Quercus spp., Castanea mollissima (Eiseman and Lonsdale 2018).

Canada: NB*, NS, ON, QC*. USA: DC, GA, IN, KS, MA, ME, NC, OK, PA, SC, TN, VA. Puerto Rico.

Holotype: USA. DC: “June”, “Collection Coquillett” (1♂, USNM; Type No. 6660).

USA. DC: “DC” (1♀, USNM), MA: Beverly, 29.vi.1876, Burgess (1♀, USNM). Puerto Rico. “Porto Rico”, Aguadilla, i.1899, A. Busck (1♀, USNM).

142♂ 97♀ 1?, CNC, USNM. Canada. NB: Kouchibouguac N.P., 8.vi.1977, J.R. Vockeroth, Code – 5222V, Code – 52336, CNC358580, CNC358581, CNC358582 (3♀, CNC), 9.vii.1977, J.F. McAlpine, Code – 6023Q, CNC358583 (1♀, CNC), QC: Rigaud, 11.vi.1981, J.R. Vockeroth, CNC358579 (1♂, CNC).

Superficially, Japanagromyza viridula can be mistaken for species of Melanagromyza because of its metallic green colouration, but it can be easily separated by the single pair of stout prescutellar acrostichal setae.

There was an error produced in the Japanagromyza key in Spencer and Stegmaier (1973) that was perpetuated in Spencer and Steyskal (1986b) and Wiegmann (1991), leaving the only Delmarva species unidentifiable. Japanagromyza viridula was differentiated from U.S. congeners with prescutellar acrostichal setae (J. inaequalis (Malloch), J. aequalis Spencer and J. polygonivora Wiegmann (= J. polygoni Spencer) by having the “mesonotum predominantly black”. Upon examination of the types of all of these species deposited in the USNM, however, there appears to be little, if any difference in the colour of the notum. Instead, J. viridula can be diagnosed by the arista, which is virtually bare (hairs not as long or longer than width of central filament) by examination of the male genitalia, or sometimes by the setulae on the ocellar tubercle, which are black or golden-brown (always black in the remaining species, which are only found in and south of Florida).