Mymarilla wollastoni (Westwood)

Huber, John T., 2013, Redescription of Mymarilla Westwood, new synonymies under Cremnomymar Ogloblin (Hymenoptera, Mymaridae) and discussion of unusual wings, ZooKeys 345, pp. 47-72 : 48-49

Mymarilla wollastoni (Westwood) Figs 1-10

Mymar wollastoni : Westwood 1879: 585 (original desciption).

Mymar wollastonii [sic]: Dalla Torre 1898: 427 (catalogue, unjustified emendation).

Mymarilla wollastoni : Annecke and Doutt 1961: 31 (redescription).

Mymarilla wollastoni : Subba Rao 1976: 90 (diagnosis), 91 (figure).

Remarks.

Lectotype female in OUMNH (not examined), designated by Annecke and Doutt (1961), with catalogue number HYME0029 and labeled: “Holotype”, "det. D.P. Annecke 25.vii.1960".

Description. Because only one species of Mymarilla is known, the generic and specific features are both described in the species description. Female. Body length 2125 (n=1). Body entirely smooth and shiny except for a few small punctures on pronotum. Colour. Head black except mandibles, mesosoma, metasoma medially, and clava; flagellum, and metasoma basally and apically dark brown; scape, pedicel, mandibles, legs, petiole, and ovipositor brownish yellow; all body setae almost white; wings brown behind venation, membrane beyond venation translucent but membrane around each microtrichia back, so wings generally appearing dark. Head. (Figs 3-6) 1.46 × as wide as long, and 1.17 × as wide as high (406/227/347) (n=1), in lateral view with anterior surface slightly depressed between toruli then, at level of ventral margin of eye, receding to mouth (Fig. 5). Face measured from eye to eye below toruli about as long as wide, flat above toruli but forming a shallow circular depression medially below toruli; subantennal groove and pits between toruli absent. Torulus about 1.5 × its diameter from thin transverse trabecula and about mid height of eye. Preorbital groove against eye almost to ventral margin of eye (Fig. 5), then extending almost straight to anterolateral angle of mouth margin. Eye (Fig. 5) in lateral view 0.75 × as long as high, not extending to back of head dorsally and separated by more than its own length from back of head ventrally. Malar sulcus absent and malar space almost 0.6 × eye height. Gena narrow dorsally, very wide ventrally. Vertex in lateral view almost flat, sloping anteriorly, forming an obtuse angle to face (separated by transverse trabecula), smoothly merging posteriorly with occiput. Mid ocellus flat in shallow depression, not projecting above surface of vertex and 2 × diameter of small lateral ocellus. Ocelli in high triangle, with POL (168), 1.9 × LOL, and LOL (89) 3.0 × OOL (30). Mandibles normal, overlapping medially when closed, with 3 teeth. Antenna. Scape about 3.9 × as long as wide, with both inner and outer surfaces apparently smooth, and with radicle short but distinct; pedicel slightly shorter than fl1, about 0.41 × scape length; funicle 6-segmented; clava unsegmented, slightly longer than scape. Number of mps of funicle segments and clava uncertain (not clearly visible on card mounted specimen). Measurements (n=1) length/width: scape 267/69, pedicel 109/50, fl1 129/20, fl2 267/20, fl3 198/30, fl4 149/30, fl5 149/30, fl6 149/30, clava 317/80. Mesosoma. About 2.67 × as long as wide, about 1.80 × as long as high, and 1.48 × as wide as high (n=1). Pronotum (Fig. 3) in dorsal view clearly visible, shorter than wide (218: 267), strongly convex, with almost vertical sides flaring outward ventrally and almost horizontal at junction with propleura; pronotum in lateral view strongly triangular. Propleura (Fig. 4) in dorsolateral view tightly pressed to pronotum laterally and anteriorly, and fused to each other at neck, and, in dorsal view (Fig. 3), slightly extending lateral to pronotum. Neck long (90), clearly separating head from pronotum. Prosternum triangular, strongly appressed laterally to propleura, without median longitudinal line, anterior apex not visible but perhaps closed anteriorly. Mesonotal spiracle (Fig. 6) small, at end of short tube, midway between posterolateral angle of mesoscutum and anterior apex of notaulus. Mesoscutum (Fig. 3) smooth and shiny, in lateral view slightly convex, in dorsal view short (99), about 0.4 × as long as pronotum and 0.4 × as long as wide, with slightly diverging, almost straight notauli, each ending anteriorly in a distinct pit. Axillae not advanced (Figs 3, 4, 9, 10). Mesoscutellum (Fig. 3) almost as long as pronotum (267: 246), slightly overlapping metanotum, without trace of frenal line (frenum therefore not distinguishable). Prepectus (Figs 6, 9, 10) triangular, about 3 × as long as dorsal width. Mesopleuron tightly appressed to prepectus, convex, not divided by suture into mesepisternum and mesipimeron. Metanotum small, triangular, separated from propodeum by wide groove. Metapleuron with a large metapleural pit at junction with mesoepisternum. Propodeum (Figs 3, 4, 7, 10) evenly convex, without carinae, with a large pit at anterior margin just anterior to spiracle, with a slightly upturned nucha covering anterior apex of petiole, and with propodeal seta almost at posterior margin. Spiracle small, round, separated by several diameters from anterior margin of propodeum. Wings. Fore wing (Figs 1, 7, 8) deeply convex, with the anterior and posterior margins strongly curving downward, the wing height in lateral view about 0.7 × wing width in dorsal view. Wing behind submarginal vein very narrow, with strongly convex hind margin, abruptly widening beginning at parastigma, generally oval in dorsal view. Entire surface to wing base covered in long microtrichia, those behind venation appressed and those beyond venation semi-erect to erect. Fore wing length 1792 (n=1), width 640, length/width 2.8, venation length 287, about 0.18 × forewing length. Submarginal vein black basally, brown apically, and much wider basally than apically; parastigma + stigma black, oval about 1.7 × as wide as base of submarginal vein. Costal cell extremely narrow. Hind wing (Fig. 1) flat to slightly convex, with long marginal setae and erect microtrichia similar to those on forewing, and wing membrane extending almost to base of wing but very narrow behind venation. Hind wing length ca. 1535, width 77, venation black, length about 0.3 × wing length. Legs. Long and slender (Figs 1, 7). Metasoma. Petiole length 180, slightly longer than metacoxa, about 6 × as long as wide. Gaster (Fig. 1) smooth and shiny, narrowly oval in cross section (as seen in posterior view), wider dorsally, almost knife-like ventrally at ovipositor. Gt1 about 0.57 × gaster length (870) and almost completely covering gs1 so petiole apparently attached to tergum, gt2-gt5 progressively shorter, gt6 and syntergum (gt7 + gt8) each about as long as gt2. Spiracle present on gt6, small. Ovipositor length ca. 770, slightly down turned apically, as long as gaster but not exserted beyond gaster, about 1.2 × metatibia length (640).

Male. Colour as in female but body dark brown (possibly due to fading), scape brownish yellow, pedicel light brown, flagellum dark brown. Body length 1843-1894 (n=2). Fore wing length 1664 (hind wing not measurable on pinned specimens), with the edges almost meeting ventrally in one specimen, giving the appearance of a hirsute cigar when seen end on in posterior view (Fig. 7). Antenna. Scape about 3.8 × as long as wide, with both inner and outer surfaces apparently smooth. Measurements (n=1) length/width or length for flagellomeres: scape 218/59, pedicel 99/45, fl1 277, fl2 267, fl3 248, fl4 248, fl5 223, fl6 228, fl7 198, fl8198, fl9 178, fl10 198, fl11 198; total flagellum 2461. Fl6 length/width about 6.0, with perhaps 8 mps (not clearly visible on card mounted specimen). Metasoma. Gaster length 742-793 (n=2), in lateral view truncate apically.

Material examined.

SAINT HELENA. Centre. High Central Ridge, Cabbage Tree Road, 2500', iii.1967, J. Decelle, N. & J. Leleup (2 males, MRAC); High Peak, 15°58.7'S, 5°44.0'W, ca.752m, xii.2005-1.2006, N.P. & M.J. Ashmole, H. Mendel, E.A. Thorpe, pitfall trap (1 female, BMNH).

Habitat.

Westwood (1879) stated that the specimens were swept from low herbage.

Annecke and Doutt (1961) suggested that the wings may be used for floating on air currents. Whether individuals are capable of this, let alone normal flight, is uncertain. The greatly reduced mesoscutum suggests that the flight muscles are so reduced they would be incapable of powered flight. The collection of one female in a pitfall trap suggests that Mymarilla wollastoni lives near the ground.