Melanagromyza matricarioides 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

Melanagromyza matricarioides Spencer

Figs 285-288

Melanagromyza matricarioides Spencer, 1969: 72. Plakidas 1982: 3.

Description.

Wing length 2.3 mm (♂). Female unknown (see variation). Length of ultimate section of vein M4 divided by penultimate section: 0.7. Eye height divided by gena height: 5.7. Gena highest behind midpoint of eye. Clypeus rounded, relatively thin and with arms slightly converging apically. Fronto-orbital plate and ocellar triangle subshiny. Fronto-orbital plate well-developed, relatively narrow, broadest behind midpoint of eye but not bulging, with swelling very shallow and indistinct; setae inset. Ocellar triangle narrow with anterior point open. Parafacial projecting dorsally.

Chaetotaxy: Two broadly separated ori; two ors. Orbital setulae in two irregular rows, becoming sparser posteriorly, erect to slightly proclinate. Ocellar setulae erect. Eye pilose in small spot dorsomedially. Two dorsocentral setae. Acrostichal setulae in eight irregular rows. Mid tibia with two posteromedial setae.

Colouration: Body, including halter, dark brown in base colour. Inner margin of fronto-orbital plate (more so anteriorly) and anterior corner of ocellar triangle sometimes light brown. Notum with faint greenish shine posteriorly (blue-green in holotype). Abdomen with green shine (bluer in holotype). Gena, notopleuron, postpronotum, and parafacial sometimes paler. Wing veins pale. Calypter margin and hairs white.

Genitalia: (Figs 285-288 ) Epandrium with small posterodistal spine. Surstylus narrow and downturned with discrete group of elongate, apical tubercle-like setae (not as figured in Spencer 1969). Hypandrium broad, short, and thick with long apical process. Metepiphallus with shallow spine and serrated ridge ventrally, and with narrow plate with several coalescing ridges laterally. Proepiphallus V-shaped and upcurved. Basiphallus U-shaped, arms relatively thick. Distiphallus separated from phallophorus by less than height of basiphallus; bases of distiphallus and mesophallus level; distiphallus with dorsomedial swelling, internal surface smooth or with remnants of spinulose internal structure (holotype), and with thick distoventral plate and dorsal processes comprising slightly narrowed apex.

Variation: Of the two non-type specimens mentioned in the original description, only the female could be located. This specimen differs as follows: wing length 2.6 mm; eye height divided by gena height 5.1; eye with smaller patch of setulae dorsally adjoining eye; fronto-orbital plate more abruptly bulging at midpoint to ~ ¼ width of frons, setulae in up to three irregular rows; abdomen with green shine. Possibly not conspecific, although most other possible local species to which it may belong in the M. virens group have the head longer towards the dorsum, and none except this species are known from Anthemis .

Hosts.

Asteraceae subfamily Asteroideae - Matricaria matricariodes , Anthemis sp., A. cotula , Rudbeckia laciniata [?].

Distribution.

Canada: ON. USA: MD, PA[?].

Type material.

Holotype: Canada. ON: Ottawa, em. 4.vii.1955, ex. "stem mine in pineapple weed" [ Matricaria matricarioides ], leg. G. Lewis, reared J.F. McAlpine, CNC358428 (1♂, CNC; Type No. 10366).

Additional material examined.

Canada. ON: Ottawa , 25.vii.1962, J.R. Vockeroth, em. 26.vii.1962 from cultivated Anthemis (1♀, CNC) . USA. MD: Ft. Detrich, 29.vi.1976, SWT Batra, AC- 1 ex. Anthemis cotula L. (1♂, USNM) .

Comments.

The Maryland male presents the second record of Melanagromyza matricarioides in the United States following Plakidas (1982), who reared specimens from Rudbeckia laciniata in western Pennsylvania. Multiple adults from one or more Pennsylvania localities were recorded from 26 August to 3 October. The specimens were originally identified by G. Steyskal, and it is unknown why they were excluded from Spencer and Steyskal (1986b); only one specimen could be relocated, and examination has found this male to be Melanagromyza virginiensis (see below).

This species belongs to the Melanagromyza virens group, revealed by the widely spaced ori, and by the surstylus, which is incredibly similar to that of M. virens itself, although the long palisade-like setae are arranged in a much more discrete apical cluster. The distiphallus is slightly more compressed dorsoventrally (not teardrop-shaped) and has one pair of characteristic shallow carinae along the dorsolateral margin.

Figures

Figures 285 - 288. Melanagromyza matricariodes Spencer, male genitalia 285 external genitalia (including subepandrial sclerite), ventral 286 phallus and proepiphallus, ventral 287 hypandrial complex, left lateral 288 hypandrium, ventral.