Cerodontha (Poemyza) muscina (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) muscina (Meigen)

Figs 101 , 545-549

Agromyza muscina Meigen, 1830: 177.

Agromyza marginata Loew, 1869: 49. Frick 1957 [synonymy].

Agromyza vittata Meigen. Misidentification. Strobl 1880: 37.

Dizygomyza ( Poëmyza) Dizygomyza muscina . Hendel, 1931: 44.

Phytobia ( Poëmyza) Phytobia muscina . Frick,1952a: 392, 1957: 202, 1959: 382.

Phytobia ( Poëmyza) Agromyza marginata . Shewell, 1953: 468.

Cerodontha (Poemyza) muscina . Nowakowski, 1967: 649, 1973: 104 [lectotype designation]; Spencer 1969: 132; Spencer and Steyskal 1986b: 93; Benavent-Corai et al. 2005: 12; Scheffer et al. 2007: 771; Papp and Černý 2016: 235; Černý et al. 2020: 204.

Cerodontha muscina . Boucher, 2001: 614.

Description

(Fig. 101 ). Wing length 1.7-2.5 mm (♂), 1.4-2.3 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 1.2-1.8. Eye height divided by gena height: 5.4-7.3. First flagellomere short, ovate. Arista pubescent. Lunule appearing as high or higher than wide when fronto-orbital plates cover base laterally; surface minutely pitted. Fronto-orbital plate ~ 1/4 frons width, smooth, well-sclerotised, contrasting soft, often buckled medial section of frons.

Chaetotaxy: Two ori (sometimes additional ori present on one side); two ors; slightly decreasing in length anteriorly overall, even if one seta sometimes slightly longer or shorter; sometimes with only anterior ori shorter. One sparse, irregular row of orbital setulae. Four dorsocentral setae, decreasing in length anteriorly with fourth dorsocentral more abruptly shortened, being ~ 1/3-1/2 length of first dorsocentral. Approximately six irregular rows of acrostichal setulae. Acrostichal seta absent. One pair of prominent setae apically on each palpus.

Colouration: Setae dark brown. Antenna brown with first flagellomere dark brown and pedicel yellowish, but sometimes entirely dark brown; fronto-orbital plate light yellow to yellow, with variable light brown to brown pigment that is darker anteriorly; fronto-orbital plate sometimes appearing entirely yellow, but minute brownish spots always present at base of setae and setulae medially and anteriorly; frons with minute dark brown markings between fronto-orbital plates that are denser and darker anteriorly; ocellar spot dark brown, slightly larger than tubercle, enclosed within larger, smooth yellow triangle; back of head, posterolateral corner of frons to base of inner vertical, clypeus and mentum dark brown; gena yellow to brown with cheek light brown, ventral margin dark brown, and minute, sparsely arranged medial pits below cheek dark brown; parafacial dirty yellow; lunule, face and palpus brown to dark brown; buccal cavity within clypeus covered with dense dark brown spicules. Remainder of body dark brown, subshiny, with postpronotum and notopleuron slightly paler; distal 1/3-1/2 of femora yellow, fore femur always more extensively yellow with yellow region uncommonly extending below midpoint; tibiae and tarsi slightly paler with fore leg palest; some specimens from the north uncommonly darker with fore femur only yellow on distal 1/3 and mid and hind femora yellow for length slightly exceeding width of femur apex; abdomen sometimes yellowish laterally on tergites 1-3. Wing veins brown to light brown, whitish to yellow at base. Halter light yellow. Calypter margin light brown to whitish (uncommonly darker), and hairs brown.

Genitalia: (Figs 545-549 ) Epandrium with or without supra-anal process; shorter dorsally, fused to surstylus. Surstylus directed inwards with scattered stout, short setae. Ventral process of subepandrial sclerite with broad, stout base and highly reduced, rounded distal section. Phallophorus fused ventrally to basiphallus. Basiphallus sclerotised along left surface of shaft, and partially along venter; produced anterodorsally as short, flat process. Hypophallus divided into one pair of broad, flat, distally narrowed plates. Mesophallus and distiphallus with very distinct torsion to right and slight asymmetry. Mesophallus with slightly widened, uneven base; length of stem ~ 2 × width; apical chamber globular. Distiphallus tubules relatively short, strongly twisted to right, dark and with narrow, slightly differentiated cups. Sperm pump with faint basal sclerotised patch; ejaculatory apodeme with short base expanding into narrow base of blade, which is distally expanded with margin dark.

Hosts.

Poaceae - Agropyron , Bromus , Dactylis , Echinochloa , Elytrigia , Ehrharta , Festuca , Hierochloe , Holcus , Hordeum , Lolium , Milium , Poa ( Ellis 2021).

Distribution.

Canada: AB, BC, MB, NB*, NL, NS, NT, NU, ON, QC, SK*, YT. USA: AK, CA, CT*, DC, DE*, GA, ID, IL, IN, MA, MD, MI, MN, NC, NH*, NY, OR, PA, TN, VA*, WA, WV*. Europe, Kyrgyzstan, Russia, South Korea ( Černý et al. 2020).

Type material.

Lectotype [muscina]: Germany. [not given] (1♀, NMW). [Not examined]

Holotype [ Agromyza marginata ]: USA. "Loew coll., Agromyza marginata m." (1♂, MCZ; type no. 13,438). [Not examined]

Additional material examined.

363♂ 299♀ (CNC, UDCC, USNM). New provincial/state records: Canada. NB: Chamcook, 16.viii.1957, G.E. Shewell, CNC481036 (1♀, CNC), Kouchibouguac N.P., 21.v.1977, B.E. Cooper, Code-5107K, CNC481033 (1♂, CNC), St. Andrews , 8.viii.1957, G.E. Shewell, CNC481035 (1♀, CNC), SK: Saskatoon, 9.ix.1959, J.R. Vockeroth, CNC481034 (1♀, CNC). USA. CT: Redding, 8.vi.1928, A.L. Melander (1♀, USNM), DE: Rehoboth, 18.vii.1976, Malaise trap, W.W. Wirth (3♀, USNM), New Castle Co., Newark , White Clay Creek , 11.vi.2001, sweeping, C.R. Bartlett (1♀, UDCC), NH: Mt. Madison , Dolly Copp Cmpgrd., 8-9.vii.1986, J.M. and S.H. Cumming, CNC481037 (1♀, CNC), VA: Arlington , vi.1938, J.R. Malloch (2♀, USNM), Falls Church , Holmes Run , 17.vii.1960, light trap, W.W. Wirth (1♀, USNM), 1.vii.1961 (1♀, USNM), 27.vii.1968 (1♂, USNM), Grayson Co. , 15 km S Galax at Chestnut Creek , 28.vi.1986, W.E. Steiner (1♂, USNM), Giles Co. , Mountain Lake , 7.ix.1976, G.C. Steyskal (2♂, USNM), WV: Great Cacapon to Largent , 2-3.vii.1977, Malaise trap, W.W. Wirth (1♀, USNM), Morgan Co. , near Great Cacapon, 3.vii.1983, G.F. and J.F. Hevel (1♂, USNM) .

Comments.

Cerodontha muscina is a relatively abundant species in North America with a characteristic twisted distiphallus. External structure and colouration are also relatively distinct, although it can be easily confused for the slightly paler and much less common C. kennethi .

Figures

Figures 99 - 106. 99 Cerodontha (Butomomyza) angulata (Loew), head, anterior 100 Cerodontha (Phytagromyza) frankensis Spencer, head, anterior 101 Cerodontha (Poemyza) muscina (Meigen), head, anterior 102 Cerodontha (Poemyza) incisa (Meigen), head, anterior 103 Cerodontha (Icteromyza) longipennis (Loew), head, anterior 104 Cerodontha (Xenophytomyza) illinoensis (Malloch), head, anterior 105 Cerodontha (Dizygomuza) morosa (Meigen), head, anterior 106 Cerodontha (Cerodontha) dorsalis (Loew), (K. Matz - Utah, Salt Lake City).

Figures 545 - 549. Cerodontha (Poemyza) muscina (Meigen), male genitalia 545 external genitalia, anterior 546 external genitalia, left lateral 547 ejaculatory apodeme 548 phallus, left lateral 549 phallus, ventral.