Agromyza aprilina Malloch, 1915

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 aprilina Malloch

Figs 156-160

Agromyza aprilina Malloch, 1915c: 359. Frison 1927: 192 [lectotype design.]; Frick 1957: 199 [as synonym subnigripes Malloch], 1959: 358; Spencer 1969: 36; Spencer and Steyskal 1986b: 262 [stat. reinst.].

Description.

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 " Agromyza 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.

Host.

Unknown.

Distribution.

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

Type material.

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

Paralectotype examined.

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

Additional material examined.

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) .

Comments.

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).

Figures

Figures 156 - 160. Agromyza aprilina Malloch, male genitalia 156 hypandrium and postgonite, ventral 157 external genitalia, ventral 158 external genitalia, left lateral 159 hypandrial complex, left lateral 160 phallus, ventral.

Figures 143 - 146. Agromyza albipennis Meigen, male genitalia 143 external genitalia, ventral 144 hypandrium and postgonite, ventral 145 hypandrial complex, left lateral 146 phallus, ventral.

Figures 193 - 197. Agromyza kincaidi Malloch, male genitalia 193 hypandrium and postgonite, ventral 194 external genitalia, left lateral 195 external genitalia, ventral 196 hypandrial complex, left lateral 197 phallus, ventral.