Microcercis insularis (Malloch), 2024

Foster, George A., 2024, Revision of Nearctic Microcercis Beschovski (Diptera: Chloropidae), with Synonymy of Incertella Sabrosky, Zootaxa 5481 (4), pp. 401-439 : 414-415

Microcercis insularis (Malloch)

( Fig. 19 , 31 )

Botanobia insularis Malloch, 1914: 26 . Type locality: Wallops Island, Virginia. Deposited NMNH. NEW COMBINATION Oscinella insularis . — Sabrosky 1936: 712, 714, 725 [in key, discussion, prob. jr. syn. of infesta ].

Incertella insularis . — Sabrosky 1980: 421 [n. comb.]

Diagnosis.—Ocellar triangle gray; vertex and occiput gray; postpedicel usually black dorsally around base of arista or more, yellow ventrally; prosternum gray; scutum gray, tomentose; postpronotal lobe and notopleuron gray tomentose, concolorous with scutum; pleuron gray tomentose except small spot on propleuron just below the anterior spiracle, posterior third of katepisternum and the meron polished black; femora brown to black, fore and mid tibiae yellow, hind tibia darker; tibial organ light brown; syntergite 1+2 usually brown but may be yellowish, with or without narrow yellow posterior margins; surstylus strongly angulate with a medial projection.

Description.—Body length; female: 1.20−1.70 mm; male: 1.11−1.43 mm.

Head: Ocellar triangle evenly grey tomentose; vertex and occiput gray; frons anterior half yellow, posterior half brownish; scape and pedicel brownish to yellow, postpedicel black around base of arista often extending to half of the segment, remainder yellow; arista black, pubescent; face, palps, and gena bright yellow; clypeus gray, prementum polished brown to black, labellum bright yellow; gena to eye ratio 0.20.

Cephalic chaetotaxy: Fronto-orbital setae brown to black; interfrontal setae brown to black; ocellar setae brown to black; postocellar setae black; outer vertical setae black; inner vertical setae gray; postocular setae short, fine, white; vibrissae yellow; subgenal setae yellow.

Thorax: Prosternum gray; prescutum polished black; scutum entirely gray tomentose; postpronotal lobe and notopleuron gray tomentose, concolorous with scutum; pleuron gray tomentose except small spot on propleuron just below the anterior spiracle, posterior third of katepisternum and meron polished black; katatergite dark yellow; anatergite gray; mediotergite gray tomentose; scutellum and subscutellum gray tomentose; wing length 1.02–1.43 mm, hyaline, costal ratios 0.46:0.33:0.16; fore coxa mostly dark yellow, occasionally with slight, gray tomentum on anterior surface, mid and hind coxae gray tomentose; all femora gray tomentose except base and distal tips narrowly yellow; tibiae lightly gray tomentose; tarsi yellow except 4 th and 5 th tarsomeres brown; femoral organ two rows of short warts with flattened setae as in figure 9; tibial organ grayish.

Thoracic chaetotaxy: Scapular seta absent; all scutal and scutellar setae brownish, dark.

Abdomen: Syntergite 1+2 usually brown but may be yellowish, with or without narrow yellow posterior margins. Male terminalia (fig. 31): epandrium grey tomentose, male cerci present as small lobes, sometimes barely evident; surstylus strongly angulate with a medial projection. Female cerci gray, concolorous with the rest of the abdomen.

Type material examined—A male specimen with a “TYPE” label is deposited in the NMNH type collection. Malloch (1914) noted that three specimens comprised the type series, dated June 1, 1913, collected by McAtee. No specimens matching that precise date were found in the NMNH collection, but one with a closely related date, May 29, 1913, and collected by McAtee, was discovered. Given Malloch’s omission of a holotype designation and the absence or probable misreporting of the collection date for all three specimens, the one that has been labeled as the holotype is now designated as LECTOTYPE. This specimen could have been chosen by Sabrosky with the intention of designating it as lectotype. It is in good condition with all body parts present except the left midleg and left wing. The specimen has shriveled, but the diagnostic features, particularly the pattern of the tomentum on the pleuron, can be observed, confirming the identity of this species.

It has four labels: the topmost label, [white], has “ Wallops Id. Va. May-29-1913 ” typewritten; the second label, [white], has “ W.L. McAtee collector” typewritten; the third label [red] has “ Type No. and U.S. N.M.” typewritten and “20066” handwritten; the fourth label [white] has ” Botanobia insularis Mall. ” handwritten.

There is one additional male with a paratype label in the NMNH regular collection. It is labeled Wallops Island, May 25, 1913, W. L. McAtee collector, with a red PARATYPE label. It is in good condition but is clearly M. infesta , not M. insularis .

Distribution.—Nearctic: United States (California, Connecticut, Delaware, Florida, Georgia, Maryland, Massachusetts, Mississippi, New Hampshire, New York, North Carolina, South Carolina, Texas, Virginia).

Discussion.—This species is distinguished from most other Microcercis species by its almost entirely gray tomentose scutum and the two small, polished areas, described above, of the pleuron. Also, the clypeus and prementum are dark as opposed to yellow in most other species.

Sabrosky (1936) had posited that M. insularis is probably a synonym of M. infesta , however the surstylus of M. insularis , with the medial tooth-like projection, is a conspicuous and reliable character that confirms its specific status.

Note.—This is another salt marsh and beach grass specialist and is often found along with M. infesta , M. trifeminarum and M. laytoni .

Figures

FIGURES 15–22. Microcercis morphology. 15, M. albipalpis habitus, lateral view. 16, M. bispina habitus, lateral view. 17, M. dorsata habitus, lateral view. 18, M. infesta habitus, lateral view. 19, M. insularis habitus, lateral view. 20, M. minor habitus, lateral view. 21, M. johanni habitus, lateral view. 22, M. murphyi habitus, lateral view.

FIGURES 31–38. Microcercis and Conioscinella morphology. 31, M. insularis male genitalia, posterior view. 32, M. johanni male genitalia, posterior oblique view. 33, M. minor male genitalia, posterior view. 34, M. minor male genitalia, lateral oblique view. 35, M. murphyi male genitalia, posterior oblique view. 36, M. murphyi male genitalia, lateral oblique view. 37 M. trifeminarum male genitalia, posterior oblique view. 38, C. ovalis male genitalia, posterior oblique view.