Agromyza bispinata Spencer, 1969

Lonsdale, Owen, 2021, Manual of North American Agromyzidae (Diptera, Schizophora), with revision of the fauna of the " Delmarva " states, ZooKeys 1051, pp. 1-481 : 1

Agromyza bispinata Spencer

Figs 38 , 41 , 42 , 167-174

Agromyza bispinata Spencer, 1969: 39. Spencer and Steyskal 1986b: 263; Eiseman and Lonsdale 2018: 8.

Description

(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 " Agromyza 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.

Host.

Poaceae - Elymus hystrix ( Eiseman and Lonsdale 2018).

Distribution.

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

Type material.

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).

Males examined.

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).

Females examined.

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).

Comments.

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.

Figures

Figures 37 - 44. 37 Agromyza aristata Malloch, female lateral 38 Agromyza bispinata Spencer, female lateral with detail of stridulatory file 39, 40 Agromyza kincaidi Malloch, male head (arrow indicates discrete apical tuft of hairs) 39 lateral 40 same, anterior 41, 42 Agromyza bispinata, male head 41 lateral 42 same, anterior 43 Agromyza sp., female (S. A. Marshall - Ontario, Hornings Mills) 44 Euhexomyza schineri (Giraud) (T. Murray - Massachusetts, Groton).

Figures 167 - 174. Agromyza bispinata Spencer, " typical " male genitalia 167 hypandrium and postgonite, ventral 168 phallus, ventral 169 hypandrial complex, left lateral 170 external genitalia, left lateral 171 external genitalia, posterior 172 external genitalia, anterior 173 external genitalia, ventral 174 A. bispinata, longer, multi-chambered " atypical " male (Maryland specimen), phallus, ventral.