Phytomyza sehgali Spencer, 1969

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 sehgali Spencer

Figs 819-821

Phytomyza sehgali Spencer, 1969: 274. Sehgal 1971: 376.

Description.

Wing length 2.2 mm (♂), 2.2-2.4 mm (♀). Vein dm-m absent. Eye height divided by gena height: 3.0-3.8. First flagellomere rounded, distal hairs slightly longer, especially dorsally. Cheek narrow.

Chaetotaxy: Two ori, anterior seta slightly shorter to 2/3 length; two ors, posterior seta slightly shorter. Ocellar seta slightly longer than fronto-orbitals, postocellar more so. Four dorsocentrals, one presutural, decreasing in height anteriorly. Acrostichal setulae in six rows.

Colouration: Body with slight brownish pruinosity that is slightly thicker dorsally on thorax. Head light brown with antenna, clypeus, palpus, back of head, ocellar tubercle, posterior margin of frons and fronto-orbital plate dark brown; face and gena paler, yellowish. Remainder of body dark brown, with apices of femora (more so on fore leg) yellowish, and notopleuron and postpronotum sometimes with slightly paler tint. Halter white. Calypter margin and hairs light brown. Abdomen dark brown.

Genitalia: (Figs 819-821 ) Hypandrium well-developed, rounded apically; inner lobe bent at midpoint and with two apical setae. Postgonite strongly narrow in profile, flattened medially, with one seta. Basiphallus relatively short, dark, and well-sclerotised along dorsum, weaker with irregular margin ventrally; left sclerite with ventrobasal arm. Hypophallus with well-defined and sclerotised lateral margin, sometimes fused to pair of medial plates that are somewhat H-shaped and joined ventromedially. Base of mesophallus flanked by converging rod-like paraphalli. Mesophallus constricted and angled upwards at midpoint, narrower basally, apically widening to distiphallus, with ventral suture. Distiphallus divided into one pair of narrow, shallowly sinuate tubules. Ejaculatory apodeme with short, ill-defined stem and narrow blade with clear margin; sperm pump clear with transverse sclerotised band.

Host.

Unknown - reared from “thimbleweed” (possibly Anemone sp., Ranunculaceae ) and “thimbleberry” (possibly Rubus parviflorus Nutt., Rosaceae ).

Distribution.

Canada: AB. USA: MD*.

Type material.

Holotype: Canada. AB: Edmonton, Whitemud Ck., 23.vi.1966, K.A. Spencer (1♂, CNC).

Additional material examined.

USA. MD: Elkton , 86-23, DFB, em. 1.v.1987, x Thimbleweed (1♂, UDCC), x Thimbleberry (2♀, UDCC) .

Comments.

The Maryland material examined here greatly extends he known distribution of this species, which is known for the first time in the United States.

Figures

Figures 819 - 821. Phytomyza sehgali Spencer, male genitalia 819 hypandrium and postgonite, ventral 820 hypandrial complex, left lateral 821 phallus, ventral.