Ophiomyia texana (Malloch)

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 texana (Malloch)

Figs 394-398

Agromyza texana Malloch, 1913: 319. Hendel 1931: 194 (as synonym of proboscoidea Strobl).

Ophiomyia texana . Frick 1952a: 383; Spencer and Steyskal 1986b: 259.

Ophiomyia shiloensis Spencer, 1969: 98. Spencer and Steyskal 1986b [synonymy].

Ophiomyia arguta Spencer in Spencer and Stegmaier 1973: 169. Spencer and Steyskal 1986b [synonymy].

Ophiomyia modesta Spencer, 1981: 94. Spencer and Steyskal 1986b [synonymy].

Description.

Wing length 1.8-1.9 mm (♂♀). Length of ultimate section of vein M4 divided by penultimate section: 0.8. Eye height divided by gena height: 11.0. Facial carina slender, distinct, with slender, smooth, matt facial bulb; carina not expanding immediately above bulb. Eye angled diagonally. Genal process with a broad, relatively short base approximating 60°, but apex much narrower, extending as a fine point. Clypeus strongly extended anteriorly as narrow process. Ocellar triangle with lateral margins straight to slightly concave, ending between ori and ors, but with sides produced as shallow grooves appearing sometimes to extend to lunule. Anterior margin of buccal cavity narrowed and straight. Notum shiny; bare between dorsocentrals. Crossveins separated by slightly more than length of dm-m.

Chaetotaxy: Male vibrissal fasciculus thick and upcurved, pointed, at least 2/3 length of gena. Two ori; two ors. Region between dorsocentrals smooth or with only a few anteromedial setulae. Mid tibia without posteromedial setae.

Colouration: Body, including halter dark brown. Gena and inner margin of fronto-orbital plate sometimes light brown. Wing veins dirty white to brown. Calypter margin and hairs dark brown.

Genitalia: (Figs 394-398 ) Surstylus narrow with few apical tubercle-like setae. Proepiphallus with lateral lobes clear with base lightly pigmented. Left sclerite of basiphallus very short, pale, and ill-defined apically, separate from right sclerite; right sclerite elongate, exceeding base of mesophallus. Base of mesophallus extending far past base of distiphallus excluding distinctive long basal tail-like process; distiphallus internally spinulose with paired ventral sclerotised ridges, subovate in ventral view and chevron-shaped in lateral view; with small dorsomedial spine. Ejaculatory apodeme with very large, pale blade past small flattened stem.

Host.

Brassicaceae - Rorippa , Descurainia . DE specimen collected on "spider bush", likely as an adult.

Distribution.

Canada: MB. USA: CA, DE*, TX. Bahamas. Reported by Frick (1959) as widespread from MI to WA.

Type material.

Holotype [texana]: USA. TX: Brownsville, "bred from roripa ", 27.i.1909, McMillan and Marsh (1♂, USNM; type No. 15582).

Holotype [arguta]: Bahamas. Eleuthera Is.: Hatchet Bay, nr. Alicetown, 2.iv.1953, E.B. Hayden and L. Giovannoli (1♂, AMNH). [Not examined]

Holotype [ Ophiomyia modesta ]: USA. CA: Ventura Co., Point Mugu State park, 2.iv.1977, K.A. Spencer (1♂, CAS). [Not examined]

Holotype [ Ophiomyia shiloensis ]: Canada. MB: 5mi SW of Shilo, 22.vii.1958, J.G. Chillcott (1♂, CNC).

Paratypes [ Ophiomyia shiloensis ]: Canada. MB: Churchill, 3.ix.1945, R. Richards (1♂, CNC), Treesbank, 17.viii.1958, J.G. Chillcott (1♂, CNC).

Additional material examined.

USA. DE: Newark , 12.ix.1960, spider bush, D.F. Bray (1♂, USNM) .

Comments.

Although Ophiomyia texana can be partially recognised by the long upcurved fasciculus, a relatively small, slender, smooth, matt facial bulb and a scutum that is largely without medial setulae between the dorsocentral setae, examination of the male phallus is essential for confident identification. The distiphallus is chevron-shaped in profile, the inner surface is sparsely but evenly spinulose, and the base has a tail-like process.

The Delaware record presented here significantly expands the northeastern range of this widespread but uncommon taxon.

Figures

Figures 394 - 398. Ophiomyia texana (Malloch), male genitalia 394 ejaculatory apodeme 395 external genitalia, ventral 396 hypandrium, ventral 397 hypandrial complex, left lateral 398 phallus and proepiphallus, ventral.