Phytomyza vockerothi Winkler, 2009

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

Phytomyza vockerothi Winkler

Figs 825-827

Chromatomyia nigrella Spencer in Spencer and Steyskal 1986b: 328.

Phytomyza vockerothi Winkler in Winkler et al. 2009: 289 [replacement name for Chromatomyia nigrella Spencer - secondary homonym of Chromatomyia nigrella Hendel].

Description.

Wing length 1.7-2.0 mm (♂). Female unknown. Vein dm-m absent. Eye height divided by gena height: 2.8-3.1. First flagellomere small and rounded, not much higher than scape; hairs along anterodorsal margin slightly longer. Gena strongly narrowing anteriorly; cheek narrow, weakly continuing along posterior margin of eye.

Chaetotaxy: One or two ori; one or two ors (posterior ors no more than 4/5 length of anterior ors, but both ors subequal on one side of frons in holotype); two ori and two ors only seen together in holotype, where anterior ori 1/2-length on one side and absent on other. Ocellar and postocellar setae subequal to fronto-orbitals. Four dorsocentrals, one presutural, decreasing in height anteriorly. Acrostichal setulae in four scattered rows anteriorly; Spencer and Steyskal (1986b) notes 2 rows, possibly in unexamined paratype. Intra-alar setulae reduced in number.

Colouration: Body mostly dark brown; frons, sometimes including fronto-orbital plate, paler; palpus, ventral margin of gena, first flagellomere and ocellar tubercle darker; halter white; postpronotum and notopleuron with faint yellow tint or mottling; apices of femora yellow, fore tibia sometimes paler with base faintly yellow. Notum subshiny. Calypter hairs light brown, margin paler.

Genitalia: (Figs 825-827 ) Hypandrium subtriangular in outline, inner lobe sometimes with setae. Postgonite well-developed with one seta. Phallophorus flanked by one pair of small bands. Halves of basiphallus relatively broad, flat, situated roof-like dorsally; left sclerite with ventrobasal process. Hypophallus small, directed apically, composed of one pair of small, pale, converging finger-like sclerites; holotype with sclerites more parallel and with small, faint medial sclerotised line. Paraphallus similar to sclerite of hypophallus but thicker, converging below distiphallus. Mesophallus not evident. Distiphallus ill-defined, linear with two lightly sclerotised to membranous strips. Ejaculatory apodeme small and dark with apex barely widened.

Host.

Unknown.

Distribution.

Canada: NS*. USA: MD*, NC, VA*, WV*.

Type material.

Holotype: USA. NC: Macon Co., Highlands, 3800ft, 8.v.1957, J.R. Vockeroth (1♂, CNC).

Additional material examined.

Canada. NS: Mount Uniacke , 5.viii.1958, J.R. Vockeroth, CNC480188 (1♂, CNC) . USA. MD: Colesville , 4.vi.1977, W.W. Wirth (1♂, USNM), VA: Shenandoah, Big Meadows, 2.vii.1939, A.L. Melander (1♂, USNM), Giles Co., Mtn. lake , 9.ix.1970, G. Steyskal (2♂, USNM), WV: Parkersburg , 21.vi.1970, G. Steyskal (2♂, USNM), Ritchie Co. , North Bend St. Pk., 23.vi.1970, G. Steyskal (2♂, USNM) .

Comments.

Phytomyza vockerothi is relatively difficult to diagnose externally, being similar to many other small, dark congeners, but the phallus is unmistakable. There is one pair of narrow sclerites on the hypophallus and one pair of similarly narrow paraphalli converging in front of a very pale, linear distiphallus. It is here recorded in Canada for the first time.

Figures

Figures 825 - 827. Phytomyza vockerothi Winkler, male genitalia 825 hypandrium and postgonite, ventral 826 hypandrial complex, left lateral 827 phallus, ventral.