Megabeleses crassitarsis Takeuchi, 1952

Wei, Meicai, 2010, Revision of Megabeleses Takeuchi (Hymenoptera, Tenthredinidae) with description of two new species from China, Zootaxa 2729, pp. 36-50 : 44-45

Megabeleses crassitarsis Takeuchi, 1952

( Figs. 23–29 , 46–47 )

Megabeleses crassitarsis Takeuchi, 1952: 33 , type locality: Japan Honshu Ege.

Description. Holotype: Ƥ.

Body length 11.5 mm ( Fig. 23 ). Black, without metallic tinge; fore tibia and tarsus largely, base of middle tarsus pale brown; posttergite, large spot on outer side of hind coxa, small spot on second trochanter of hind leg, basal half of hind femur yellow white; palpi blackish brown. Wings subhyaline, apical half faintly infuscate, stigma and veins black brown. Body hairs and setae on sheath silver brown.

Head dorsally coarsely punctured, bottoms of middle and lateral fovea polished, temple and postocellar area somewhat sparsely punctured; lateral lobe of pronotum coarsely punctured; mesonotum including posttergite densely punctured, posterior 2/3 of prescutum, top of scutum, anterior part of mesoscutellum sparsely punctured, parapsis microsculptured; elevated area behind cenchri coarsely punctured, metascutellum microsculptured with isolated punctures; lateral part of propleuron sparsely and ventral part densely punctured; upper half of mesepisternum and dorsal margin of mesepimeron coarsely punctured, ventral half of mesepisternum sparsely punctured with distinct shining interspaces, other part of mesepimeron microsculptured; ventral part of metepisternum very sparsely punctured, strongly shining, upper margin of metepisternum and of metepimeron densely punctured, central area of metepimeron coriaceous; outer side of hind coxa densely punctured on basal half, apical half sparsely punctured. Abdominal tergites impunctate, distinctly microsculptured (cf. Fig. 33 ); lateral sides of ovipositor sheath polished, shiny.

Anterior margin of clypeus roundly, very shallowly incised for about 1/8 clypeus length; malar space slightly shorter than radius of ocellus; closest distance between eyes 1.3× height of eye; distance between antennal sockets 0.9× distance between antennal socket and eye; middle fovea round, distinct, frons large, frontal walls obtuse; circular furrow of anterior ocellus, postocellar and interocellar furrows obscure; postocellar area distinctly elevated, 1.3× broader than long, without middle furrow; lateral furrows broad and shallow, divergent backwards; lateral margins of head behind eyes in dorsal view about 3/5 length of eye, distinctly enlarged. Antenna hardly shorter than thorax and abdomen together, third antennomere as long as fourth antennomere. Mesoscutellum slightly broader than long, anterior corner roundly protruding, obtuse; posterior margin carinate; posttergite without middle carina, apical margin round; distance between cenchri about 1.4× width of a cenchrus; dorsal lobe of metepimeron long and narrow ( Fig. 46 ). Length of inner side of 1st abdominal tergite about 1/3 length of widest lateral length. Apex of hind coxa reaching posterior margin of 5th sternite, outer side of hind tibia with a long and distinct longitudinal furrow, apex distinctly thickened; inner spur of hind tibia about 1/4 length of hind basitarsus; hind basitarsus weakly thickened with constricted base, 4.5× longer than broad, 1.1× longer than tarsomeres 2–5 together ( Fig. 28 ), outer side without distinct furrow. Vein cu-a almost interstitial to vein 1M, R+M short, 2r weakly bent at upper 1/3 and meeting cell 2Rs at middle, 2m-cu almost interstitial to 1r-m; petiole of hind anal cell about half length of cu-a. Ovipositor sheath 1.07× longer than middle tibia, apical sheath 1.4× longer than basal plate, ventral margin roundly curved, apical margin broadly rounded in lateral view ( Fig. 27 ); apical sheath in dorsal view triangular, basal width 2.5× width of cercus; setae on lateral sides of apical sheath slightly longer than diameter of ocellus; cercus about 2.5× as long as broad. Lancet with 25–26 serrulae, middle serrulae each with about 30 distinct subbasal teeth, inner incision of serrulae distinct ( Fig. 47 ); membranous lobe of lance slightly narrower than middle width of lance.

Male: Body length 10 mm ( Fig. 24 ). Colour and structure similar to female, except for: basal 1/4 of hind femur yellow white, middle tibia and tarsus pale brown; malar space about 1/3 diameter of ocellus; closest distance between eyes 1.16× broader than height of eye, lateral sides of head behind eyes parallel in dorsal view; postocellar area with a shallow middle furrow; distance between cenchri 1.85× width of cenchrus; vein 2r meeting cell 2Rs at apical 1/3; subgenital plate 1.1× longer than broad, apical margin round; genitalia as Fig. 25 , harpe longer than broad; penis valve as Fig. 26 , apex with deep incision in dorsal side.

Distribution. Japan (Hiroshima ( Takeuchi, 1952), Niigata ( Okutani, 1973), Hyogo ( Naito, 2004) and Ishikawa ( Togashi, 2008) of Honshu; Higo of Kyushu (Takeuchi, 1952)) ( Fig. 51 ).

Naito (2004) mentioned that M. crassitarsis Takeuchi also distributes from Hokkaido of Japan and give a reference as Togashi (1970). In fact, Togashi (1970) did not mention M. crassitarsis in the paper at all. Possibly Naito read Megatomostethus crassicornis (Rohwer) as Megabeleses crassitarsis Takeuchi.

Specimens examined. 1Ƥ, holotype, “ 8.V.1937, Ege, Hirosima [Hiroshima], Takeuchi”; “Huixia, 1937.5.8, Nakanish[i]”; “ Megabeleses crassitarsis Take , Holotype ” ( Fig. 29 , OPU). 13, paratype: “Takaoyama, 13.VII. [wrongly recorded as VI. in the original description] 1932, J. Sonan”; “ Megabeleses crassitarsis Take , allotype” (OPU).

Host plants. Magnolia kobus DC., Michelia compressa Maxim (reported as “ Michelia compressa Sarg. ”) ( Okutani, 1970). No other biological characteristics have been reported.

Discussion. Togashi (2008) pointed out seven differences between M. crassicornis and M. tsurugiensis , most of which are incorrect: 1. In M. crassicornis the apex of sawsheath rounded in lateral view (nearly truncate in M. tsurugiensis )[not true, comparing Figs. 27 and 36 ]; 2. The hind tibia as long as hind tarsus (hind tibia longer than hind tarsus in M. tsurugiensis ) [the hind tibia is also longer than hind tarsus in M. crassicornis ]; 3. Hind basitarsus as long as following four tarsomeres together (hind basitarsus longer than following four tarsomeres together in M. tsurugiensis )[not true, comparing Figs. 28 and 35 ]; 4. Vein 2m-cu interstitial with 1r-m (not interstitial with 1r-m in M. tsurugiensis )[the vein 2m-cu is close to (not interstitial with) 1r-m in M. crassicornis and this character varies in different specimens within a species in the genus]; 5. The posterior margin of mesoscutellar appendage (posttergite) triangular (rounded in M. tsurugiensis ) [not true, both are rounded]; 6. Hind basitarsus without a longitudinal furrow on the outer side (with a longitudinal furrow in M. tsurugiensis ) [true]; 7. Serrulae each with about 16–18 subbasal teeth (with about 45 subbasal teeth in M. tsurugiensis ) [comparing Figs. 37 and 47 , middle serrulae of M. crassicornis each with about 30 subbasal teeth, and in M. tsurugiensis with about 20 subbasal teeth]. Only one of the above seven differences is entirely true. Togashi (2008) also mentioned that the length of antenna of M. tsurugiensis is different from M. crassicornis , but he did not compare the character state between the two species. Examination of the antennae of the two holotype females show that there is no distinct difference between the two species: both antennae are about as long as vein C and stigma together, or about as long as thorax and abdomen together.

See the above key for the differences between the two species.

Figures

FIGURE 51. Distribution records of Megabeleses spp.

FIGURES 23 – 29. Megabeleses crassitarsis Takeuchi, 1952. 23. Adult, female; 24. Adult, male; 25. Genitalia; 26. Penis valve; 27. Apical sheath, lateral view; 28. Hind tarsus; 29. Labels of holotype.

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.

FIGURES 30 – 38. Megabeleses tsurugiensis Togashi, 2008. 30. Adult, female; 31. Head, dorsal view; 32. Clypeus; 33. Microsculpture on abdominal tergites; 34. Mesoscutellum and posttergite; 35. Hind tarsus; 36. Apical sheath, lateral view; 37. 10 th serrula; 38. Labels of holotype.