Megadineura leucotarsis Wei

Wei, Meicai & Nie, Haiyan, 2008, A new species of Megadineura Malaise (Hymenoptera: Tenthredinidae) and a key to the known species of the genus, Zootaxa 1920, pp. 51-60 : 53-55

Megadineura leucotarsis Wei , new species ( Fig. 1 )

Diagnosis: The species differs from the three other known species in the genus in its yellow-white clypeus, labrum, dorsal side of the scape, tegulae, outer margin of pronotum, concave parts of metanotum, basal 4/5 of hind tibiae and all tarsi;,distinctly compressed antennae in the female; vein R+M in forewing longer than first free abscissa of vein M, lower outer corner of cell 2M hardly extended; petiole of hind anal cell longer than half length of cu-a; ventral margin of tangium distinctly concave and sheath in dorsal view strongly tapering toward apex.

Description. Holotype: Ψ.

Body length 13 mm. Black, with yellow-white palpi, labrum, clypeus, superclypeal area largely, dorsal side of scape and two apical antennomeres, broad outer side of pronotum, tegulae, lateral sides of post-tergite and concave parts of metanotum; legs yellow-white, with fore and middle coxae largely, basal 3/5 of hind coxae, posterior side of fore femur, middle femur, hind femur (except for extreme base and basal half dorsally), apical 1/4 of hind femur and all tibial spurs black, fore and middle tibiae brown at apex. Wings hyaline, apical half feebly infuscate, stigma and veins black. Body hairs silver, black parts of antennae and legs with black-brown hairs ( Fig. 1 a).

Head dorsally impunctate, without microsculpture, shining; thorax dorsally and ventral part of mesepisternum shallowly and minutely punctured, shining; mesoscutellum and post-tergite evenly punctured; upper half of mesepisternum densely and coarsely rugose, mesepimeron and metapleuron finely microsculptured, abdominal tergites densely microsculptured, impunctate, somewhat shining. Malar space 1/3 diameter of ocellus; clypeus flat, broad, without ridge, incision in anterior margin 1/3 length of clypeus ( Fig. 1 b); labrum broad, apically rounded; inner margins of eyes feebly convergent downwards, distance between eyes slightly wider than height of eye (25:23); middle fovea very deep, round, closed; lateral foveae deep and open anteriorly; frontal wall developed, frontal basin distinct; interocellar furrow shallow, extending to posterior margin of head, postocellar furrow broad, very shallow; postocellar area elevated, 3 times as broad as long, lateral furrows short and convex; POL: OOL: OCL = 4: 4: 3; head behind eyes 1/3 length of eyes in dorsal view, laterally parallel. Antennae stout, compressed, slightly shorter than thorax and abdomen together, third segment curved, clearly shorter than each of 4th, 5th and 6th segments. Setae on head and thorax dense, about as long as diameter of an ocellus. Prescutum without middle furrow but with fine middle carina; mesoscutellum flat, without furrow; mesepisternum roundly elevated, without oblique ridge. Apical spurs of hind tibia half length of basitarsus, as long as apical width of tibia; basitarsus slightly longer than following 3 tarsomeres together; claw without basal lobe, inner tooth shorter than outer tooth. First abscissa of vein M in forewing distinctly bent at base, almost parallel with 1m-cu, slightly shorter than R+M; Sc basad of vein R+M; 2r joining cell 2Rs at its basal 3/7; cell 2Rs shorter than 1Rs as 6: 7, more than 2 times as long as broad; cu-a joining cell 1M at apical 2/5; cell 2M slightly longer than broad, hardly extending outward ventrally. Petiole of hind anal cell 1A 3/5 length of vein cu-a. Seventh sternite of abdomen as in Fig. 1 c. Sheath strongly tapering toward apex in dorsal view, cerci long, projecting beyond end of sheath ( Fig. 1 d); sheath in lateral view as long as middle tibia ( Fig. 1 e). Lancet elongate and triangular with 23 serrulae, annular sutures almost straight, upper and middle parts of sutures 1 to 17 each with a row of very short spines; tangium remote from first serrula, ventral margin distinctly concave ( Fig. 1 f); serrulae oblique and protruding, basal serrulae each with about 12–13 subbasal teeth, middle serrulae each with 6–8 subbasal teeth; 6th to 7th serrulae as in Fig. 1 g.

Male: unknown.

Variation: The three type specimens are very much alike.

Etymology: The new species is named after the white tarsi. The other known species of the genus all have black tarsi.

Specimens examined: Holotype: 1Ψ, Foping, Shaanxi (33.5ºN, 107.9ºE), alt. 1000–1450 m, 17 May, 2005, LIU Shou-Zhu coll.; paratypes: 2 Ψ, Liuba, Shaanxi (33.44.937ºN, 107.08.343ºE), alt. 1250 m, 18 May, 2007, Jiang Xiao-Yu 2Ψ, Honghuapuzhen (33.44.221ºN, 107.10.544ºE), alt. 1080 m, 25 May, 2007, Zhu Xun (Types are deposited in the Insect Collection of Central South University of Forestry and Technology (CSUFT), Changsha, China).

Figures

FIGURE 1. Megadineura leucotarsis Wei, sp. nov., female. (a). Adult (b). Clypeus (c). 7 th sternite (d). Sheath in dorsal view (e). Sheath in lateral view (f). Tangium (g). 6 th to 7 th serrulae.