Megabeleses xiaoi Wei

Wei, Meicai, 2010, Revision of Megabeleses Takeuchi (Hymenoptera, Tenthredinidae) with description of two new species from China, Zootaxa 2729, pp. 36-50 : 38-40

Megabeleses xiaoi Wei , sp. nov.

( Figs. 1–7 , 39, 43, 49 )

Description. Holotype: Ƥ.

Body length 9 mm ( Fig. 1 ). Black, head, thorax, abdomen, legs almost entirely and basal part of antenna with strong metallic blue tinge; outer side of hind coxa with a large white spot, basal 3/5 of hind femur dorsally with white stripe; fore and middle tibiae and their tarsi largely pale brown, ventral sides of tibiae black brown. Wings evenly infuscate, stigma and veins black brown. Body hairs silver.

Frons, posterior orbit and inner orbit densely and minutely, temple and postocellar area sparsely punctured, clypeus coarsely reticulate; anterior part of prescutum densely, middle part of scutum coarsely, posterior part of prescutum and other part of scutum sparsely punctured; anterior part of mesoscutellum polished, almost impunctate, lateral and posterior parts very densely punctured; posttergite coarsely reticulate; elevated area behind cenchri in metathorax densely punctured, metascutellum and bottom of each parapsis (or parascutellar area) finely and densely microsculptured; punctures on upper and central part of mesepisternum large and very dense, interspaces linear, ventral part of mesepisternum evenly punctured; mesepimeron densely microsculptured, upper margin densely punctured; ventral side of metepisternum very sparsely punctured, strongly shining, upper margin of metepisternum and of metepimeron densely punctured; central area of metepimeron weakly microsculptured. Outer side of hind coxa densely punctured, interspaces narrow. First abdominal tergite very densely punctured, posterior margin polished; other tergites evenly punctured; lateral sides of sheath largely polished, shiny.

Anterior margin of clypeus very shallowly incised for about 1/8 clypeus length; malar space 0.4× diameter of ocellus; closest distance between eyes 1.3× height of eye; distance between antennal sockets 0.8× distance between antennal socket and eye; middle fovea deep, frontal walls broad and low, circular furrow of anterior ocellus and postocellar furrow obscure, interocellar furrow shallow; postocellar area weakly elevated, 1.25× broader than long, with a shallow medial furrow; lateral furrows broad, shallow, slightly divergent backwards; lateral margins of head behind eyes (lateral margins of tempora) in dorsal view about half length of eye, weakly narrowed; occipital carina fine but distinct, extending to upper part of hind orbit. Antenna 1.25× longer than abdomen, third antennomere 1.15× longer than fourth antennomere. Mesoscutellum 1.45× broader than long, anterior corner roundly protruding, obtuse; posterior margin sharply carinate; posttergite with a middle carina, apical margin round ( Fig. 39 ); distance between cenchri 1.5× width of a cenchrus; dorsal lobe of metepimeron short and broad ( Fig. 43 ). Length of inner margin of 1st abdominal tergite about half length of widest lateral length. Apex of hind coxa reaching middle of 4th sternite, hind tibia laterally without distinct longitudinal furrow, apex weakly thickened; inner spur of hind tibia 0.36× length of hind basitarsus; hind basitarsus slightly thickened with constricted base, about 6× as long as broad, 1.15× longer than tarsomeres 2–5 together. Vein cu-a interstitial to base of 1M, R+M punctiform, 2r weakly bent and meeting cell 2Rs at apical 3/7, 2m-cu interstitial to 1r-m; petiole of anal cell in hind wing slightly shorter than half length of cu-a. Ovipositor sheath as long as middle tibia, apical sheath 1.4× longer than basal plate, ventral margin almost straight in lateral view ( Fig. 3 ); apical sheath in dorsal view very narrow, basal width equal to breadth of cercus, setae on apical sheath as long as diameter of ocellus ( Fig. 4 ). Lancet with 25 serrulae, middle serrulae each with about 45 very minute subbasal teeth ( Fig. 49 ); membranous lobe of lance distinctly broader than middle width of lance.

Male: body length 8 mm ( Fig. 2 ). Colour and structure similar to female, except for: hind femur without white stripe dorsally; malar space linear, head short and distinctly narrowed behind eyes in dorsal view; subgenital plate as long as broad, apical margin obtusely truncate; dorsal apical corner of valviceps triangularly protruding ( Fig. 5 ), ventral part of valviceps with 3–4 rows of minute teeth ( Fig. 6 ); harpe about as long as broad, apical margin oblique ( Fig. 7 ).

Distribution. China (Hunan) ( Fig. 51 ).

Etymology. The new species is named after Mr. Xiao , the collector of a paratype.

Specimens examined. Holotype: Ƥ, Huangsang, Suining, Hunan Province, alt. 600–900 m, 22 April, 2005, Meicai Wei. Paratypes: 13, Huangsang, Suining, Hunan Province, alt. 600–900 m, 22 April, 2005, Wei Xiao ; 13, Huangsang, Suining, Hunan Province, alt. 600–900 m, 21 April, 2005, Yang Lin (CSCS).

Host plant. Unknown.

Remark. This new species is close to M. liriodendrovorax Xiao, 1993 . See the above key for the differences between the two species.

Figures

FIGURE 51. Distribution records of Megabeleses spp.

FIGURES 1 – 7. Megabeleses xiao, sp. nov. 1. Adult, female; 2. Adult, male. 3. Ovipositor sheath, lateral view; 4. Apical sheath, dorsal view; 5. Penis valve. 6. The magnified quadrate part of Fig. 5; 7. Harpe.

FIGURES 39 – 50. Megabeleses spp. 39 – 41. Mesoscutellum and posttergite, dorsal view; 42. Mesoscutellum and posttergite, lateral view; 43 – 46. Metepimeron; 47 – 50. 10 th serrula. 39, 43, 49, M. xiaoi; 41, 42, 44, 50, M. magnoliae; 40, 45, 48, M. liriodendrovorax; 46, 47, M. crassitarsis.