Mesembrina Meigen

Kuchta, James S. & Savage, Jade, 2008, Revision of the new world fauna of Mesembrina Meigen (Diptera: Muscidae) with the description of a new neotropical species, Zootaxa 1689, pp. 29-50 : 32-34

Genus Mesembrina Meigen

Mesembrina Meigen, 1826: 10 . Type species: Musca meridiana Linnaeus, 1758 , subsequent type designation by Westwood (1840).

Eumesembrina Townsend, 1908: 50 , 124. Type species: Mesembrina latreillii Robineau-Desvoidy, 1830 , original designation.

Metamesembrina Townsend, 1908: 50, 124. Type species: Musca meridiana Linnaeus, 1758 , original designation.

Neomesembrina Schnabl & Dziedzicki, 1911: 226. Type species: Musca meridiana Linnaeus, 1758 , monotypy.

Hyperdermodes Townsend, 1912: 46. Type species: Musca mystacea Linnaeus, 1758 , original designation.

Diagnosis: Mesembrina can be distinguished from other Muscidae by the following combination of characters: large size (over 7 mm in length), prosternum bare, anepimeron setulose, thorax and abdomen covered with very fine dense black and/ or yellow hairs, wing base intensely yellow (except in M. nigribasis ), lower calypter truncated and of the “ Musca - type ”, and apical portion of M1 vein curved to varying degrees.

Description. Male: body length 8.8–14.9mm.

Head: Background color usually black, sometimes brown; holoptic; parafacial and gena dusted silver to brown or yellow; eye sparsely haired except in Mesembrina montana Zimin where it is bare; distance between eyes 1.0–1.5x distance between the outer margins of the posterior ocelli; frons with 6–10 fine black medioclinate fr and with abundant weaker medioclinate, proclinate or reclinate orb, tuft of short black setae posterior to ocellar triangle except in M. decipiens where they can be yellow, 1 convergent i vt always present and 1–3 pavt; palpus orange and/or black, 5.0–7.0x as long as wide, pedicel orange-black, always haired and with 2 setae, more than 2x length of others, first flagellomere 3.0–4.0x as long as wide ranging in color from orange to black; arista plumose with longest hair 1.5x width of first flagellomere, basal half of arista thickened, black or yellow, prementum haired and glossy, 2.0–2.5x as long as wide.

Thorax: Glossy black, bluish or greenish; covered in fine black or yellow hairs; postpronotal lobes and medial portion of prescutum dusted white, giving the appearance of 3 distinct white lines on the dorsal surface, these lines absent in Mesembrina tristis Aldrich, M. montana , M. decipiens and M. mystacea who all have very dense hair on the thorax; anepimeron haired with a tuft of longer hairs on dorsal edge; dorsal thoracic bristles usually black, occasionally yellow; 0–2 + 1–2 acr, 0–5 + 1–4 dc, 0–1 + 0–2 ial, 1 + 4–7 spal, 3 npl, 2 pal, anepisternum bare anteriorly; 0–1 a kepst, 1–3 p kepst; postpronotum haired, with 2–3 strong ppnl; prosternum bare; scutellum glossy black-reddish, scutellar setae usually black, sometimes yellow, 1 pair of apical sctl, 6–8 pairs of lateral sctl.

Legs: Mostly black, fifth tarsomere flattened on all legs and occasionally yellowish, pulvilli large, 2.0x as long as wide on all legs except in Mesembrina intermedia Zetterstedt where they are as long as wide, claws with a black tip and a bright yellow or dark reddish base; F1 with 1 row of equal pd on basal two-thirds, 1 row of p decreasing in size from base and 1 complete row of sub-equal v; F2 with a cluster of 2–5 p near apex; F3 with 1 row of sub-equal av and ad, usually with av and ad stronger on apical third; T1 with very fine and short a giving the surface a shiny brown look, 1 strong ad near apex and 1 strong d, either standing alone or as part of a row; T2 usually straight with 1 ad, 5–6 p and 2 v. In M. decipiens and M. mystacea T2 elongated and noticeably curved towards apex, with 1 row of 7–8 strong p sub-equally spaced, 1 row of fine brown pv increasing in length apically but of equal length on apical third and 1 row of equal v eventually converging with pv, whereas in M. nigribasis T2 is not curved or elongated but does have 1 ad, 7–8 p and 1 row of pv; T3 with 1 long pd near midpoint, and often with 1 d near apex; fore tarsomeres: 1>2>3>4<5, often but not always with distinct ventral yellow line starting from the midpoint of tarsomere 1 extending to apex of tarsomere 5; mid tarsomeres: 1>2>3>4<5, usually without distinct ventral yellow line extending from the midpoint of tarsomere 1 to apex of tarsomere 5 but if line present then usually dull yellow; hind tarsomeres: 1>2>3>4<5, with or without distinct ventral yellow line extending from the midpoint of tarsomere 1 to apex of tarsomere 5, usually covered with very fine brown short p giving the tarsomeres a shiny look, but in Mesembrina magnifica Aldrich and Mesembrina aurocaudata Emden these short fine p are yellow.

Wing: Mostly clear with heavy yellow tinge on basal half (as in Figs. 1 D, 1E), except in M. nigribasis where the base is black ( Fig. 1 F), apical half occasionally with brown tinge surrounding veins; wing veins yellow on basal half and brown on apical half except in M. nigribasis where they are black basally, yellow medially and brown apically; M1 ending before ( Fig. 1 F) or past ( Figs. 1 D, 1E) the wing apex; alula yellow, brown or black; calypters yellow, brown or black; lower calypter broad, truncate posteriorly, its posterior margin following scutellar margin before diverging away; haltere with orange stalk and bulb black.

Abdomen: Shiny black except in M. aurocaudata where fifth abdominal tergite is partly orange; densely covered in fine black or yellow hairs, when yellow hairs present, these usually restricted to tergites 3–5; third and fourth tergite with l m and 1 row of m m along the margin, if not present then tergites covered with very dense hair; sternite 5 1.1–1.2x as long as wide.

Postabdomen: Epandrium wider than high ( Fig. 2 B) except in M. latreillii and Mesembrina resplendens Wahlberg where it is much higher than wide ( Fig. 4 B); mesolobus at least as high as wide ( Fig. 2 B) with outer ventral projection usually longer than inner projection (except in Mesembrina nudiparafacia Fan where the outer projections are shorter than the inner ones), outer projection in M. decipiens and M. latreillii with sharp tooth-like protrusion near apex ( Figs. 2 A, 2B, 4A); surstylus short with shape in posterior view variable ( Figs. 2 B, 4B, 5B), pregonite with base wide and apex slender, with 1–4 lateral setae ( Figs. 2 C, 4C, 5C); postgonite 1.0–2.0x as high as width of base, with apex rounded and base slightly concave with several small lateral setae, epiphallus 0.5–1.0x as long as phallapodeme with apex forked ( Figs. 2 C, 5C) or rounded ( Fig. 4 C); apex of phallapodeme sometimes club-shaped ( Fig. 2 C); ejaculatory apodeme well sclerotized ( Fig. 2 C); lateral sclerites of distiphallus broad and weakly sclerotized, apical section of lateral sclerites with sparse spinules ( Fig. 2 C), dorsal sclerite of distiphallus underdeveloped ( Fig. 2 C).

Female: body length 7.0–20.0mm. Differs from male as follows:

Head: Dichoptic, distance between eyes 4.2–5.5x distance between the outer margins of the posterior ocelli, tuft of short setae posterior to ocellar triangle black but occasionally yellow in some specimens of M. decipiens and M. mystacea , frontal vitta black to reddish, sometimes with many fine frontal setulae; 6–17 medioclinate fr, stronger anteriorly, usually 2 strong proclinate orb located medially except in M. nigribasis that has none and 1–2 strong reclinate orb located posteriorly on head, surrounded by fine yellow or black proclinate orb 0.5x the length of larger orb and extending only to the medial portion of the frontal vitta or all the way to the parafacial.

Thorax: Usually as in male, but in M. decipiens and M. mystacea yellow setae denser and in M. decipiens yellow setae usually extending onto the anepisternum.

Legs: T2 never elongated or curved, with 2–3 pv on basal two-thirds and other bristles variable; T3 usually with 1 long d near apex; fore tarsomere usually without distinct ventral yellow line, mid and hind tarsomeres without ventral yellow line.

Wing: As in male, with apex occasionally ending in smoother tip and M1 vein less abruptly bent near the apex.

Abdomen: Third abdominal tergite with distinguishable m m except in M. decipiens , M. mystacea , M. tristis and M. nigribasis who all have denser hair. On the fifth abdominal tergite, M. latreillii , M. “ resplendens subspecies” of Hennig, M. meridiana and M. intermedia have 2 patches of dense short hairs that are approximately 0.5x as long as surrounding hairs (Fig. 6A).

Postabdomen: Anterior portion of tergite 8 split longitudinally into 2 rectangular parallel rods, posterior plate of tergite 8 with 5–9 robust sub-equal setae ( Fig. 3 A); anterior portion of sternite 8 split longitudinally into 2 club-shaped parallel plates, posterior plate of sternite 8 with 3–6 robust sub-equal setae ( Fig. 3 B); tergite 10 bare except for 1–2 pairs of setae on the posterior margin, if present, medial pair smaller ( Fig. 3 A); cercus bare, cercal pegs small ( Figs. 3 A, 5B); spermathecae 2.0x as long as wide ( Fig. 3 C).

Figures

FIGURE 1. Males of M. decipiens (A, D, G), M. latreillii (B, E, H) and M. nigribasis (C, F, I). A – C. Whole habitus, lat-

FIGURE 2. Male of M. decipiens. A. External genitalic structures, lateral view. B. External genitalic structures, posterior view. C. Internal genitalic structures, lateral view. D. Sternite 5, ventral view.

FIGURE 3. Female of M. decipiens, apical portion of ovipositor. A. Dorsal view. B. Ventral view. C. Spermatheca.

FIGURE 4. M. latreillii. A. Male external genitalic structures, lateral view. B. Male external genitalic structures, posterior view. C. Male internal genitalic structures, lateral view. D. Male sternite 5, ventral view. E. Female apical portion of ovipositor, dorsal view. F. Female apical portion of ovipositor, ventral view. G. Female spermatheca.