Ichneumonosoma triangularis Chen & Norrbom, new species

Ichneumonosoma triangularis Chen & Norrbom, new species

(Figs. 41–48; 49–56)

Ichneumonosoma imitans: Hancock & Drew 1995: 55, misidentification.

Diagnosis. Head with 1 frontal seta and large polished triangular black mark over ocellar tubercle and dorsomedian portion of occiput and vertex extended anterolaterally to eye margin. Scutum with pair of large, somewhat Lshaped presutural black marks; pair of large somewhat inverted J-shaped postsutural black marks. Wing almost completely hyaline, with narrow fuscous costal band extending beyond vein R4+5 and slight infuscations over crossvein R-M and crossvein DM-Cu. Abdomen yellow to yellow-brown, with narrow black bands on posterior margin of each of syntergite 1+2 and tergites 3–6 in female, and syntergite 1+2 and tergites 3–4 in male.

Description. A large predominantly yellow to fulvous species. Female (Figs. 41, 42): body length 12.2 mm; wing length 8.9 mm. Male (Figs 49, 50): body length 12.3 mm; wing length 9.8 mm.

Head (Fig. 51). Completely yellow to fulvous except large opaque triangular black mark on anterior median portion of frons, large polished triangular black mark over ocellar tubercle and dorsomedian portion of occiput and vertex, extended anterolaterally to eye margin, and antennae dark brown. Head slightly broader than thorax in dorsal view and distinctly higher than wide in lateral view. Orbital plates with dense fine setulae. Frons about 1.3– 1.5 times as long as wide, and about as wide as eye in dorsal view. Antenna slightly shorter than face; 1st flagellomere about 3 times as long as pedicel, 3 times as long as wide, apex rounded; arista short plumose. Occiput convex, distinctly swollen ventrally. Head setae black: 1 frontal and 1 lateral vertical setae. Orbital, medial vertical, postocellar and genal setae absent. Dorsal 1/3 of frons with numerous fine black setulae.

Thorax (Fig. 45). Predominantly yellow to fulvous except for following black marks: pair of large somewhat L-shaped presutural scutal marks (composed of submedial vitta and band along anterior margin of transverse suture); and pair of large, somewhat inverted J-shaped postsutural marks (composed of submedial spot connected to dorsocentral vitta and band on posterior scutal margin); pair of large somewhat J-shaped postsutural scutal marks; 1 broad band on anepisternum; and 2 broad vittae on mediotergite. Scutum about 1.5–1.6 times as long as wide, with transverse suture complete and deep. Thoracic chaetotaxy: 2 pairs scapular, 1 dorsocentral, 1 scutellar, 1 postprontal, 2 notopleural, 1 postsutural supra-alar, 1 postalar, 1 intra-alar, 1 anepisternal, 1 anepimeral setae present; prescutellar acrostichal seta absent. Scutellar seta situated closer to apex than to base of scutellum. Wing (Fig. 52) almost completely hyaline, with narrow fuscous costal band extending from pterostigma to beyond apex of vein R4+5 and slight infuscations over crossvein R-M and crossvein DM-Cu; cells bc and c hyaline; veins R1 and R4+5 setulose dorsally, the latter distinctly beyond level of crossvein DM-Cu; crossvein R-M situated beyond middle of cell dm; cell bcu with posterodistal lobe short and broad, forming angle of approximately 45º. Legs predominantly yellow to fuscous except mid and hind femora with basal part dark brown, hind tibia with basal half dark brown; mid tibia with 2 large black apicoventral spurs. All femora, tibiae and tarsi covered with numerous black short fine hairs except for fore femur.

Abdomen. Female (Figs 44, 46): Abdomen yellow to yellow-brown, with narrow black bands on posterior margin of each of syntergite 1+2 and tergites 3–6, and 2 narrow lateral black bands at sides of tergite 2. Tergites 3, 4 and 5 about same length. Oviscape cylindrical, about as long as tergites 5+6; aculeus laterally compressed at tip, with median dorsal and ventral ridge bearing distinct serrations, lacking preapical setae (tip of aculeus triangular in lateral view, very acute in dorsal view). Male (Fig. 53): Abdomen yellow to yellow-brown, with narrow black bands on posterior margin of each of syntergite 1+2 and tergites 3–4, and a narrow longitudinal black band at middle of tergite 5.

Distribution: Malaysia (Kuala Lumpur).

Type data: Holotype ♂ (AMS), MALAYSIA (W): Templar park nr Kuala Lumpur, 18 April 1985, D.K. McAlpine; Paratype 1♀ (AMS), MALAYSIA (W): On Frasers Hill Rd. 76km from Kuala Lumpur, 30 July 1986 K.C. Khoe.

Etymology. The name of this species is an adjective in reference to the triangular black mark dorsally on the head.

Remarks. This species is similar to I. imitans, differing by the triangular shape of the black mark over the ocellar tubercle and dorsomedian portion of the occiput and vertex which extends anterolaterally to the eye margin, the orbital plates with dense fine setulae, and the katepisternum and meron lacking black markings. The holotype was illustrated (as I. imitans) by Hancock & Drew (1995, fig. 11).