Nematus soidaoi Smith, 2011

Smith, David R., 2011, Nematinae (Hymenoptera, Tenthredinidae) of Thailand, with notes on some other southeastern Asian nematines, Journal of Hymenoptera Research 22, pp. 1-27 : 8-10

Nematus soidaoi Smith sp. n. Figs 11-13

Description.

Female. Length, 7.5 mm. Antenna and head black; spot at center of clypeus, labrum, and mouthparts white. Thorax black with posterior half of pronotum and tegula white. Abdomen and sheath black. Foreleg mostly white, coxa at apex, trochanter, femur except basal and apical parts black; midleg mostly white, coxa at apex and apex of tibia and apical 4 tarsomeres brown to black; hind leg with coxa at apex white, femur black with extreme basal and apical parts white; tibia with two-thirds white, apical third black; basitarsomere with basal half white and apical half black, rest of tarsomeres black. Wings hyaline, veins and stigma black.

Head and body smooth, shiny, without punctures; with fine white pubescence. Antennal length 2.3 × head width; 3rd antennomere subequal in length to 4th antennomere. Clypeus roundly emarginated anteriorly. Malar space equal to diameter of front ocellus. Left mandible bulbous at base, apical portion slender. Lower interocular distance 1.3 × eye height. Distance between eye and hind ocellus 0.7 × distance between hind ocelli; postocellar area about 2.6 × broader than long. Forewing with intercostal crossvein present, basal to M; 3 cubital cells. Hind basitarsomere about 0.8 × length of remaining tarsomeres combined; pulvilli large, almost equal to breadth of tarsomeres, on tarsomeres 1-4. Hind tibia with longitudinal groove on outer surface. Tarsal claws with long inner tooth, slightly shorter than outer tooth. Inner hind tibial spur about half length of hind basitarsomere and slightly longer than apical width of hind tibia at apex. Sheath in dorsal view broad at base with slight, rounded scopae much shorter than central portion, central portion acuminate at apex, with long setae arising from scopae; in lateral view straight above, rounded below ( Fig. 13 ). In dorsal view, cerci equal to sheath length. Lancet ( Fig. 13 ) with serrula long, lobelike, length more than 2 × width.

Male. Unknown.

Holotype.

Female, labeled "Thailand, Soi Dao, 500-1850 m, sweep, UTM 1429610, Jan. 16, 2005, Sharkey" (QSBG).

Etymology.

The species name is derived from the type locality.

Discussion.

This species is assigned to Nematus by similarity of the long inner tooth of the tarsal claws, emarginated clypeus, and similar wing venation. I have not seen any species of Nematus with such long, lobelike serrulae ( Fig. 13 ). The basal rounded portion of the sheath with long setae representing small lateral scopae (as can be seen in the lateral view in Fig. 13 ) is also unusual for species of Nematus , most of which have an evenly slender sheath in dorsal view. Because the lancet is partly exerted and the long serrulae are diagnostic, I have not dissected the specimen for a close-up of the lancet.

Figures

Figures 11 - 13. Nematus soidaoi, holotype 11 Lateral view 12 Head, front view 13 Sheath and lancet.