Phytoliriomyza pilosella Spencer, 1973

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

Phytoliriomyza pilosella Spencer

Figs 711-715

Phytoliriomyza pilosella Spencer in Spencer and Stegmaier 1973: 116. Spencer and Steyskal 1986b: 153.

Description.

Wing length 1.5 mm (♂), 1.3-1.6 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 1.8-2.0. Eye height divided by gena height: 3.8-10.5. Eye minutely setulose dorsally. Vein r-m near basal 1/3 of cell dm. Frons soft medially.

Chaetotaxy: One ori; two ors. Postocellar and ocellar setae well-developed, but not much longer than ocellar tubercle. Orbital setulae proclinate, in one row. Four dorsocentrals, one presutural, decreasing in length anteriorly with anterior two pairs considerably thinner and smaller, being <1/2 length of first dorsocentral. Several acrostichal setulae in two rows anteriorly that are often reduced to absent. Hairs on first flagellomere slightly longer than, or as long as arista base.

Colouration: Frons brownish with tubercle brown; face, gena and parafacial light yellow; male first flagellomere lightly infuscated posteriorly; female first flagellomere and pedicel light brown, sometimes yellowish ventrally or basally. Notum brown with grey pruinosity, anterolateral margin of scutum yellow, and anatergite below scutellum darker; postpronotum and notopleuron yellowish; yellowish postsutural supra-alar stripe sometimes visible. Pleuron yellow with most of katepisternum and meron brown, remainder with limited, narrow spots sometimes visible, including anteroventrally and sometimes anteriorly on anepisternum. Apical surface of halter light brown. Calypter margin and hairs faintly brownish. Legs yellow with base of fore coxa light brown, tibiae brownish distally and tarsi brownish with distal segments darker; dorsal brown mottling faint apically on mid and hind femora, more developed subapically and apically on fore femur, pigment pronounced in [dissected] Ontario male and Californian specimens. Abdomen light brown, paler laterally and apically, epandrium yellow, oviscape brown to yellow with partial brown markings.

Genitalia: (Figs 711-715 ) Epandrium rounded apically and with one tubercle-like seta on inner-distal margin. Surstylus narrow, curved, emerging from anterior margin of epandrium, with several apical setulae. Subepandrial sclerite H-shaped with lateral margins bowed. Hypandrium thin with lobe broad and bare. Postgonite narrowly rounded and cleft apically. Basiphallus sclerotised on dorsal margin. Paraphallus and hypophallus absent. Mesophallus not evident. Distiphallus composed of one pair of extremely elongate, narrow, clear tubules with base dark and slightly swollen. Ejaculatory apodeme stout, pale and fan-shaped with stem very short; sperm pump with lightly sclerotised band.

Variation: Specimens from California with brownish palpus, specimens from Florida and Costa Rica with dark brown palpus. Florida specimen with narrow, distinct yellow postsutural intra-alar line and complete dorsocentral line; with enlarged setula in front of anterior dorsocentral; setulae on eye virtually absent.

Host.

Asteraceae - Cotula ( Spencer 1990).

Distribution.

Canada: ON*. USA: CA*, FL, KY*, MD*, MS*, VA*. Costa Rica. Puerto Rico. Spain (Canary Islands).

Type material.

Holotype: Puerto Rico: El Yunque, 20-22.iii.1954, J. Maldonado and S. Medina (1♂, USNM).

Paratypes examined.

Costa Rica. San Jose: La Caja, 8 km W, 1930, Schmidt, CNC481318 (1♀, CNC). Puerto Rico. El Yunque, 20-22.iii.1954, J. Maldonado Capriles (1♀, USNM). USA. FL: Dade Co., Farm near Royal Palm Hammock, 4.xii.1961, Munroe, Holland and Chillcott, CNC481317 (1♀, CNC).

Additional material examined.

Canada. ON: Puslinch , Property of Bob Hanner, 43°26'47.04"N, 80°15'4.32"W, hardwood forest, 3.viii.2008, T. Terzin, CNC481319 (1♂, CNC) . USA. CA: Marin Co., Alpine Lk., Lily Pond , 457 m, 17-25.v.1971, Malaise trap, CNC481320, CNC481321 (1♂, 1♀, CNC), iv-v.1970, D.D. Munroe, CNC481323-481325 (3♀, CNC), v-vi.1970, CNC481322 (1♀, CNC), KY: Lexington , 2.xi.1915, J.M. Aldrich (1♂, USNM), MD: “ChespkBch” “viii-2”, J.M. Aldrich (1♀, USNM), MS: Noxubee National Wildlife Refuge , near Bluff Lake , River Road, 33°17'12"N, 88°46'42"W, 65 m, 18-19.v.2013, J.E. O’Hara, Malaise trap, CNC758941 (1♀, CNC), VA: Falls Church, Holmes Run, 13.ix.1960, light trap, W.W. Wirth (1♀, USNM) .

Comments.

Phytoliriomyza pilosella is a small, delicate species most readily diagnosed by longer hairs on the first flagellomere and a long, clear coiled tubular distiphallus. The new material listed here represents a significant Nearctic range extension for this species since it was only otherwise known as far north as the southern tip of Florida.

Spencer (1990) recommended additional study of this species in comparison to Phytoliriomyza scotica Spencer, which may be conspecific. Re-evaluation of the boundaries of this species is also recommended here, due to variation in palpus and antenna colour, but also chaetotaxy. The long-haired first flagellomere is also seen in P. minutissima Spencer, but this differs in having a medially yellow scutellum.

Figures

Figures 711 - 716. Phytoliriomyza pilosella Spencer, male genitalia 711 external genitalia, ventral (subepandrial sclerite shaded) 712 external genitalia, left lateral 713 hypandrium and postgonite, ventral 714 hypandrial complex, left lateral 715 phallus, ventral 716 P. clara (Melander), phallus, ventral.