Cerodontha (Poemyza) pygmaea (Meigen)

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

Cerodontha (Poemyza) pygmaea (Meigen)

Figs 550-554

Agromyza pygmaea Meigen, 1830: 183.

Dizygomyza pygmaea . Hendel, 1920: 135.

Dizygomyza (Poemyza) pygmella Hendel, 1931: 48. Spencer 1969 [synonymy].

Dizygomyza (Poemyza) verrucosa Hendel, 1931: 51. Nowakowski 1973 [synonymy?].

Dizygomyza (Poemyza) pygmaea . Hendel, 1931-1936: 46.

Phytobia (Poemyza) pygmaea . Hennig, 1953: 138.

Phytobia pygmaea . Kubska, 1961: 34.

Cerodontha (Poemyza) pygmaea . Nowakowski, 1962: 112, 1967: 651, 1973: 127; Spencer 1969: 133; Spencer and Steyskal 1986b: 279; Benavent-Corai et al. 2005: 12; Scheffer and Lonsdale 2018: 87.

Phytobia (Poemyza) verrucosa . Rohdendorf, 1970: 251.

Description.

Wing length 2.1-2.5 mm (♂), 2.4-3.2 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 1.9-2.2 (2.4-3.2 in European specimens). Eye height divided by gena height: 6.0-8.3. Arista short pubescent. First flagellomere ovate, length equal to or slightly greater than height. Ring around eye narrow but strong. Lunule narrow, up to 1/2 length of frons, minutely pitted. Frons slightly wider compared to other Poemyza , resulting in fronto-orbital plate being less than 1/4 width of frons. Anterior region of fronto-orbital plate slightly expanded, covering lateral base of lunule; inner margin clearly delimited, but not as strongly sclerotised or raised, as in other Poemyza .

Chaetotaxy: Two ori; two ors; relatively stout. Ocellar and postocellar setae slightly shorter and thinner than fronto-orbitals. Orbital setulae in single row. One pair of prominent setae apically on each palpus. Four dorsocentral setae, decreasing in length anteriorly with fourth seta 1/3-2/5 length first seta. Acrostichal setulae in six scattered to irregular rows. Acrostichal seta relatively strong to slightly developed, not much larger than surrounding setulae.

Colouration: Setae dark brown. Head dark brown, with back of head, ventral margin of gena, face, clypeus and palpus darker; ocellar spot darker, relatively small; centre of frons with dense, deep minute pits; gena often slightly paler; space between clypeus with minute dark brown spicules. Body dark brown, subshiny, with moderate greyish brown pruinosity; postpronotum and notopleuron slightly paler; apex of fore femur and base of fore tibia light yellow for length equal to width of femur apex; apex of mid and hind femora faintly and narrowly yellowish, or entirely dark brown. Wing veins brown, only yellow at very base. Halter light yellow. Calypter margin and hairs dark brown.

Variation: Delmarva specimens with highly reduced pruinosity on body, appearing shinier; acrostichal setae absent. English specimens with apex of mid femur nearly as pale as fore femur.

Genitalia: (Figs 550-554 ) Epandrium with supra-anal process; anteroventral margin weakly sclerotised; fused to surstylus. Surstylus small, directed inwards, with short thin setae. Ventral process of subepandrial sclerite with broad, stout base and short apical section with irregular outer margin. Basiphallus ventrally fused to phallophorus; sclerotised along ventral and left lateral surfaces with anterodorsal process extending along right distal surface. Hypophallus broad and flat, becoming thinner and paler apically; M-shaped with slight basomedial carina and other lesser striations. Left paraphallus present, directed laterally, meeting base of mesophallus. Mesophallus stem swollen subbasally in ventral view, much more so in lateral view, and dorsoventally compressed to narrow distal point of fusion with apical chamber; apical chamber with broad, bilobed base that broadly overlaps stem. Distiphallus tubules elongate, question mark-shaped, clear, with narrow sclerotised band on inner surface on basal 1/2, and complete narrow outer band reaching small apical cup. Ejaculatory apodeme with small, narrow blade.

Host.

Poaceae - Agropyron , Agrostis , Ammophila , Apera , Arrhenatherum , Avena , Avenula , Brachypodium , Bromus , Calamagrostis , Dactylis , Deschampsia , Drymochloa , Elymus , Festuca , Glyceria , Holcus , Hordeum , Lolium , Melica , Milium , Molinia , Phalaris , Phleum , Phragmites , Poa , Secale , Setaria , Triticum ( Ellis 2021).

Distribution.

Canada: BC*, NL, ON, QC. USA: AK, DE*, MD*, NY, TN*, WV*. Europe. Russia.

Type material.

Holotype [pygmaea]: Germany [not given]. [Lost].

Holotype [verrucosa]: Finland. Birkkala (1♂ UZMH). [Not examined].

Syntypes [ Dizygomyza pygmella ]: Russia. Far East: Kamtschatka. Ozernaja, coll. Wuorentaus (2♂ 2♀ UZMH).

Additional material examined.

Austria. Oberösterreich: Linz, 16.vii.1962, Hering, mine an Dactylis glomerata Nr. 6804, CNC481163 (1♀, CNC). Canada. BC: Terrace, 50 mi SW, around and on wet cliff face, 9.vii.1960, J.G. Chillcott, CNC481213 (1♀, CNC), NL: St. John’s, Agric. Exp. Sta., 12.vii.1967, J.F. McAlpine, Malaise trap, CNC481218, CNC481219 (2♀, CNC), 9.viii.1967, CNC481216, CNC481217 (2♀, CNC), St. John’s, Agric. Exp. Sta., on Ranunculus , 18.vii.1967, J.F. McAlpine, CNC481214, CNC481215 (2♀, CNC), Stevenville, 19.vi.1979, B.V. Peterson, CNC481220 (1♀, CNC), ON: Dundas, 27.v.1955, O. Peck, CNC481209 (1♀, CNC), Normandale, 29.v.1956, J.R. Lonsway, CNC481185 (1♂, CNC), Point Pelee, 7.vii.1980, D.L. Krailo, CNC481210 (1♀, CNC), Pt. Pelee, 7.vii.1980, S. Beierl, CNC481211 (1♀, CNC), Simcoe, 2.vi.1939, G.E. Shewell, CNC481167 (1♂, CNC), QC: Fort Chimo, on Solidago , 2.vii.1954, J.G. McAlpine, CNC481208 (1♀, CNC). USA. AK: Anchorage, 15.vi.1953, R.S. Bigelow, CNC481189, CNC481190 (2♀, CNC), 18.vii.1953, CNC481171 (1♂, CNC), 26.vi.1951, CNC481168 (1♂, CNC), 27.vi.1951, CNC481186, CNC481188 (2♀, CNC), 27.vi.1953, CNC481169 (1♂, CNC), 29.vi.1951, CNC481187 (1♀, CNC), 29.vi.1953, CNC481170 (1♂, CNC), Chowiet Island (Aleutian), 56°2'5.82"N, 156°44'25.14"W, prairie meadow, 10.vii.2009, Goulet and Boudreault, sweeping, CNC340749 (1♂, CNC), Cold Bay, on tundra, 21.viii.1952, W.R. Mason, 163°W, CNC481173 (1♂, CNC), King Salmon, Naknek, 11.vii.1952, W.R. Mason, CNC481198 (1♀, CNC), 6.vii.1952, CNC481184, CNC481199 (1♂ 1♀, CNC), 4.vii.1952, CNC481200 (1♀, CNC), 3.viii.1952, CNC481182, CNC481183 (2♂, CNC), 13.vii.1952, J.B. Hartley, CNC481205 (1♀, CNC), 13.viii.1952, CNC481207 (1♀, CNC), 3.vii.1952, CNC481201-481203 (3♀, CNC), 4.vii.1952, CNC481204 (1♀, CNC), 4.viii.1952, CNC481181 (1♂, CNC), 5.viii.1952, CNC481180 (1♂, CNC), 8.viii.1952, CNC481206 (1♀, CNC), Naknek, on tundra, 2.viii.1952, W.R. Mason, CNC481179 (1♂, CNC), 21.vii.1952, CNC481174 (1♂, CNC), CNC481172-481196 (1♂ 4♀, CNC), 8.viii.1952, CNC481178 (1♂, CNC), 9.viii.1952, CNC481176 (1♂, CNC), 3.vii.1952, J.B. Hartley, CNC481175, CNC481177, CNC481197 (2♂ 1♀, CNC), Unalakleet, 18.vii.1961, R. Madge, CNC481191 (1♀, CNC), 24.vii.1961, CNC481192 (1♀, CNC), DE: Rehoboth, 18.vii.1976, Malaise trap, W.W. Wirth (1♀, USNM), MD: Colesville, 28.v.1977, W.W. Wirth (1♀, USNM), 4.vi.1977 (1♀, USNM), 14.vi.1977 (1♀, USNM), TN: Gr. Sm. Mt. Nat. Park, Indian Gap, 1554 m, 24.vii.1957, J.G. Chillcott, CNC481212 (1♀, CNC), WV: Morgan Co., near Great Cacapon, 3.vii.1983, G.F. and G.F. Hevel (1♀, USNM). England. Chippenham Fen., Cambs., 5.vii.1958, [K.A. Spencer], Brachypodium Syl. em. 19.vii.1958, CNC481166 (1♀, CNC), Hering, mine an Brachypod. silvaticum em. 27.vii.1958, 6315, CNC481162 (1♂, CNC), Marlow, Buck., 11.vii.1954, [K.A. Spencer], Gramineae [em.] 26.vii.1954, CNC481164 (2♂ / ♀, CNC), Scratch Wood, Mddx., [K.A. Spencer], em. 20.vii.1956, CNC481165 (1♀, CNC).

Figures

Figures 550 - 554. Cerodontha (Poemyza) pygmaea (Meigen), male genitalia 550 external genitalia, anterior 551 external genitalia, left lateral 552 ejaculatory apodeme 553 phallus, left lateral 554 phallus, ventral.