Ophiomyia tiliae (Couden)

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

Ophiomyia tiliae (Couden)

Figs 399-404

Agromyza tiliae Couden, 1908: 35.

Melanagromyza tiliae . Frick 1952a: 380, 1957: 200 [lectotype designation].

Melanagromyza fastosa Spencer, 1969: 67. Syn. nov.

Hexomyza tiliae . Spencer 1973: 299.

Ophiomyia fastosa . Spencer and Steyskal 1986b: 255.

Ophiomyia tiliae . Spencer and Steyskal 1986b: 260.

Description.

Wing length 1.9-2.7 mm (♂), 2.7-3.3 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6-0.8. Eye height divided by gena height: 2.5-4.3. Fronto-orbital plate varying from slightly visible laterally to relatively pronounced; parafacial sometimes produced, continuing under eye as broad cheek. Gena relatively high and shallowly rounded, only slightly angled anteriorly to produce shallow ventromedial angle. Facial carina indistinct to absent, but antennal bases always slightly separated; bulb slender, not strongly pronounced, usually appearing as slight swelling below antennal bases. Clypeus stout and parallel-sided. Ocellar triangle and fronto-orbital plate shiny. Crossveins narrowly separated.

Chaetotaxy: Male vibrissal fasciculus absent. Two to three ori (orbital setula between ori variably strengthened); two ors. Mid tibia with one posteromedial seta.

Colouration: Body, including halter dark brown with gena paler. Wing veins light brown. Calypter margin and hairs brown. Abdomen sometimes with very faint, almost indistinct metallic lustre - in NY male, tint greenish with tergites 1-3 bluish.

Genitalia: (Figs 399-404 ) Externally as described for O. abutilivora , excluding texturing on epandrium. Phallophorus strongly compressed laterally. Basiphallus ring-shaped and with adjoining dorsobasal membrane lightly sclerotised. Distiphallus subspherical with anterior and ventral margins thick; ventrally bordered by light transverse sclerite (upcurved and pointed at sides; highly faded in tiliae holotype, likely resulting from method of preservation as other specimens reared from Tilia with this sclerite moderately to well-developed), long thin membranous flagellum (pointed ventrally) and large carinate, membranous hypophallus.

Variation: VPIC male with clypeus appearing broadly rounded (actually bulbous medially), but anterior corners still present. Cheek only evident anteriorly. Two ori, closely spaced anteriorly. Anteroventral membrane on phallus reduced, with “wings” of distiphallus barely evident.

Host.

Malvaceae - Tilia americana , Tilia sp.

Distribution.

Canada: AB, ON*, QC. USA: CO, IL, IN, MA ( Eiseman and Charney 2010), MO, NY*, PA, VA.

Type material.

Lectotype [tiliae]: USA. MO: Jennings, 4.iv.1907, T.F. Hickey, ex. Tilia americana (1♀, USNM; type No. 10,028).

Paralectotypes examined

[tiliae]: USA. MO: Jennings, Mrs. Hickey, coll., 2.iv.1907, iss. 10.iv.1907 (1♀, USNM), 2.iv.1907, iss. 4.iv.1907 (3♀, USNM), 2.iv.1907, iss. 6.iv.1907 (1♀, USNM), 22.iii.1907, iss. 10.iv.1907 (1♀, USNM), 22.iii.1907, iss. 7.iv.1907 (1♀, USNM).

Holotype [fastosa]: Canada. QC: Hull, 24.v.1923, C.H. Curran (1♂, CNC).

Additional material examined.

Canada. ON: Brantford , 24.i.1978, “775-2306-01”, " Tilia R’rd” (1♂ 2♀, CNC), Col. 17.viii.1977, Host Tilia americana , feeding gall at base of petiole (1♂, CNC) . USA. CO: State Bridge nr. Bond , 7000', 24-25.vi.1961, B.H. Poole (1♂, CNC), NY: Ithaca , 22.v.1950, J.C. Martin, CNC358463 (1♂, CNC), VA: Fairfax Co., Great Falls Park , quarry, 38°59.1'N, 77°14.8'W, Malaise trap, 24.iv-2.v.2007, D.R. Smith (1♂, USNM), Turkey Run Park, nr. mouth of Turkey Run, 38°57.9'N, 7°09.4'W, Malaise trap, D.R. Smith, 26.iv-2.v.2007 (1♂, USNM), 5.v-6.vi.2006 (1♂, USNM), Blacksburg, 5.v.1947, W.B. McIntosh (1♂, VPIC) .

Comments.

Ophiomyia tiliae is much darker than similar species such as O. abutilivora and often has a much higher gena. An ovate distiphallus with a ventrally directed apical flagellum and bordered by a wide transverse sclerite are most diagnostic.

Ophiomyia fastosa syn. nov. is here included as a junior synonym of O. tiliae , which overlaps in wing length, gena height, colour and chaetotaxy. Morphology of the surstylus/epandrium are also similar, as is morphology of the phallus, with variations seen in previously published illustrations of the distiphallus being strongly exaggerated or not evident upon re-examination.

Male genitalic illustration of Ophiomyia parvella Spencer ( Spencer and Stegmaier 1973; Sasakawa 1994) almost exactly matches the genitalia of O. tiliae , and may also be conspecific. While the host of O. parvella is unknown, the host of O. tiliae ( Tilia americana , American basswood is found in Florida ( USDA 2008), where O. parvella was described from. Ophiomyia shastensis Spencer has highly similar genitalia, but apparently differs from O. tiliae in having a metallic abdomen; the metallic tint is evident in some specimens examined here, including those in the northeast, suggesting that the boundaries of this species require future re-examination.

Figures

Figures 399 - 404. Ophiomyia tiliae (Couden), male genitalia 399 ejaculatory apodeme 400 phallus, ventral 401 phallus, left lateral 402 holotype phallus, ventral 403 external genitalia, ventral 404 external genitalia, left lateral.