Phytobia waltoni (Malloch)

Figs 690-692

Agromyza waltoni Malloch, 1913a: 303.

Phytobia (Phytobia) waltoni . Frick, 1952a: 391, 1959: 377.

Phytobia waltoni . Spencer, 1969: 109; Spencer and Steyskal 1986b: 272.

Description

(Fig. 690). Wing length 3.2-3.9 mm (♂), 3.6-4.0 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 1.1-1.5. Costa extending to vein M. Space between cross-veins ~ 1/2 length of dm-m, but sometimes nearly 2/3 length. Eye height divided by gena height: 3.2-3.6. Frons well-sclerotised; ocellar triangle indistinct. Space between antennae ~ 2/3-3/3 width of scape. Clypeus stout and broad, width equal to length, length at midpoint longer than epistoma. Epistoma shallow and broad. Frons shiny around base of fronto-orbitals (pruinose in other species).

Chaetotaxy: Three ori; two ors (inset). Postocellar seta as long as ors; ocellar seta slightly longer. Four dorsocentrals, one presutural, slightly decreasing in size anteriorly. One pair of strong prescutellar acrostichal setae, subequal to dorsocentrals. One usually indistinct posteromedial mid tibial seta.

Colouration: Head dark brown with lunule orange to brown. Thorax brown to dark brown with orange-reddish tint (paler on postpronotum and notopleuron, particularly on anterior margin, or with pale spot on either side of postpronotum) and brownish grey pruinosity; halter yellow. Calypter margin and hairs dark. Legs and abdomen brown to dark brown.

Genitalia: (Figs 691-692) Inner lobe of hypandrium broadly arched anteriorly with apex setulose. Postgonite narrow with apex broadly expanded dorsally and with one inner seta. Basiphallus relatively short with well-developed recurved subapical branch. Hypophallus with one pair of narrow, weakly pigmented and textured plate-like lobes with truncated, serrated apical margins. Paraphallus absent. Mesophallus narrow, ~ 1/2 length of distal section, broadly rounded basally, narrowed apically to point of fusion with bulbous base of distiphallus. Distiphallus split along most of length into two narrower tubules with flared apex; base surrounded by membranous fringe with paired leaf-like processes anteriorly. Ejaculatory apodeme short, blade reduced to stump; sperm pump with reduced ventral sclerotisation.

Host.

Unknown.

Distribution.

Canada: NB*, QC. USA: IA, NC, NH*, NY, SC, TN*.

Type material.

Holotype: USA. NY: "Amer. Sept. Horv., 1907", Adirondack, Long Lake (1♀, USNM; type No. 15572).

Additional material examined.

Canada. NB: Kouchibouguac N.P., 10.vii.1977, J.F. McAlpine, Code - 6025S, CNC391826 (1♂, CNC), 11.vii.1977, Code - 6026T, CNC391822, CNC391823 (2♂, CNC), 12.vii.1977, Code - 6040H, Code - 6041I, CNC391829, CNC391830, CNC391825 (3♂, CNC), 13.vii.1977, Code - 6042J, CNC391832-391824, CNC391827 (4♂, CNC), 6.vii.1977, Code - 6039G, CNC391831 (1♂, CNC), 9.vii.1977, Code - 6023Q, Code - 6023a, Code - 6024R, CNC391819-391821, CNC391828 (3♂ 1♀, CNC), 12.vii.1977, J.R. Vockeroth, CNC391836 (1♀, CNC), 12.vii.1978, S.J. Miller, Code - 7250V, CNC391835 (1♂, CNC), 22.vii.1978, Code - 7325S, CNC391834 (1♂, CNC), QC: Mt. Albert, 28.vii.1954, J.E.H. Martin, CNC391817, CNC391818 (2♀, CNC) . USA. NC: Smokies, Andrews Bald, 9.vii.1941, A.L. Melander (16♂ 3♀, USNM), Great Smokies N.P., Clingmans Dome, A.L. Melander, 18.vii.1941 (5♂, USNM), 19.vii.1941 (1♂, USNM), Great Smokies N.P., "Newfnd Ridge", 11.vii.1941, A.L. Melander (9♂ 2♀, USNM), Smokies, Forney Ridge, 26.vi.1941, A.L. Melander (1♂, USNM), NH: Lost River, vii.1931, A.L. Melander (1♂, USNM), Franconia Ntch, 8.vii.1931, A.L. Melander (1♂, USNM), TN: Smokies, Arch Rock, 28.vi.1941, A.L. Melander (1♂, USNM) .