Lamachus rufiabdominalis Li, Sheng & Sun

Li, Tao, Sheng, Mao-Ling & Sun, Shu-Ping, 2012, Species of the genus Lamachus Foerster (Hymenoptera, Ichneumonidae) parasitizing diprionid sawflies (Hymenoptera, Diprionidae) with descriptions of two new species and a key to Chinese species, ZooKeys 249, pp. 37-49 : 39-40

Lamachus rufiabdominalis Li, Sheng & Sun sp. n. Figures 715

Etymology.

The specific name is derived from the red metasoma.

Types.

Holotype, female, CHINA: Weining, Guizhou Province, 14 March 2012, leg. Tao Li, Mao-Ling Sheng. Paratypes: 51 females and 26 males, CHINA: Weining, Guizhou Province, 3 March to 15 April 2012, leg. Tao Li, Mao-Ling Sheng.

Diagnosis.

Malar space 0.5 times as long as basal width of mandible. Postocellar line as long as ocular-ocellar line. Antenna with 46 to 48 flagellomeres. Fore wing with vein 1cu-a slightly distal of 1/M. Vein 2-Cu approximately as long as 2cu-a. Hind wing vein 1-cu about as long as cu-a. First tergum 2.5 times as long as apical width. Median and apical portions of second tergum, third to fifth terga red.

Description.

Female (Fig. 7). Body length 7.0 to 10.0 mm. Fore wing length 7.0 to 9.0 mm.

Head. Inner eye orbits weakly concave at level of antennal insertions. Face (Fig. 8) 0.9 times as wide as long, with dense punctures, upper center with median longitudinal groove. Clypeus smooth, weakly convex at basal portion, 2.5 times as wide as long; apical portion distinctly concave, with fine wrinkles. Mandible smooth, with fine punctures, upper tooth slightly longer than lower tooth. Malar space with fine leathery texture and dense punctures, 0.5 times as long as basal width of mandible. Gena with texture as that of malar space. Vertex (Fig. 9) smooth, with fine leathery texture. Ocellar triangle weakly convex. Postocellar line about equal to ocular-ocellar line. Middle portion of frons evenly convex, with texture as that of vertex. Lateral portion of frons evenly concave. Antenna with 46 to 48 flagellomeres, ratio of length from first to fifth flagellomeres: 10.0:6.0:6.0:6.0:5.0. Occipital carina complete.

Mesosoma. Anterior portion of pronotum with fine leathery texture and dense punctures; upper part of median portion with weak wrinkles; lower part of median portion with dense punctures; upper posterior portion with dense punctures. Mesoscutum evenly convex, with dense punctures. Notaulus weak. Scutoscutellar groove wide, with weak longitudinal wrinkles. Scutellum evenly convex, with texture as that of mesoscutum. Postscutellum transverse, punctures finer than on scutellum. Middle and lower portions of mesopleuron (Fig. 10) convex, with texture as that of mesoscutum. Upper portion of mesopleuron with rough punctures. Speculum small, with fine granulose texture. Lower portion of speculum weakly concave. Metapleuron evenly convex, with texture as that of mesopleuron. Submetapleural carina complete. Ratio of length of hind tarsomeres 1:2:3:4:5 is 10.0:5.0:3.5:2.0:2.0. Fore wing with vein 1cu-a weakly outside of 1/M. Vein 2-Cu approximately as long as 2cu-a. Fore wing with stalked triangular areolet. Vein 3rs-m distinct longer than 2rs-m. Areolet receiving vein 2m-cu approximately at lower-posterior angle. Hind wing vein 1-cu about as long as cu-a. Propodeum (Fig. 11) evenly convex, without areas, with texture as that of mesoscutum. Propodeal spiracle circular, located at about anterior 0.3 of propodeum.

Metasoma. First tergum 2.5 times as long as apical width, with fine leathery texture and sparsely punctate. Spiracle circular, small, located at middle of first tergum. Dorsolateral carina complete posterior to spiracle. Ventrolateral carina complete. Second tergum (Fig. 12) approximately 0.8 times as long as apical width, with texture as that of first tergum and apical portion sparsely punctate. Thyridium circular. Ovipositor sheath approximately 0.3 times as long as hind tibia. Ovipositor with dorsal notch. Basal portion of ovipositor very wide. Apical portion distinctly slender.

Color (Fig. 7). Black, except the following. Middle portion of face (width of fleck 0.75 times as long as that of face in holotype, width of fleck 0.60 to 0.86 times as long a s width of face among individuals), clypeus, mandible except black teeth, front portion of fore coxa and first trochanter, part of anterior of mid coxa, hind corner of pronotum, fleck of propodeum, yellowish green. Anterior side of fore femur, tibia and tarsus, apical portion of mid femur, tibia and tarsus, yellowish brown. Hind tibia entirely black, or subbasally with a small, indistinctly yellowish spot. Central and apical portion of second tergum, third to fifth terga, red. Pterostigma and veins brownish black. Wings brownish hyaline.

Male. Body length about 7.0 to 9.0 mm. Fore wing length about 5.0 to 7.0 mm. Antenna with 48 flagellomeres. Face, coxa and front portion of trochanters of fore leg, coxa and front portion of trochanters of mid leg, yellowish green. Hind tibia entirely black. Other characteristics as for female.

Host.

Neodiprion huizeensis Xiao & Zhou ( Hymenoptera : Diprionidae ).

Host plant.

Pinus armandi Franch. ( Pinaceae ).

Remarks.

This new species is similar to Lamachus iwatai Momoi 1962, but can be distinguished from the latter by the following combination of characters: first tergum 2.5 times as long as apical width; hind tarsomere 4 as long as tarsomere 5; inner orbit, malar space and mesoscutum entirely black. Lamachus iwatai : first tergum 1.7 times as long as apical width; hind tarsomere 4 shorter than tarsomere 5; inner orbit, malar space, a median spot of mesoscutum, yellow.

Biology.

Lamachus rufiabdominalis is an endoparasitoid of Neodiprion huizeensis larvae. The mature larva of Lamachus rufiabdominalis is cream-colored (Fig. 13), the color changing continuously as development continues. The body of the pupa is yellowish white, compound eyes and ocelli, red. After four days, the compound eyes became black, ocelli changed to reddish brown and the teeth red (Fig. 14). One day later, the ventral profile of the mesothorax, anterior portion of median lobe and lateral portion of lateral lobe of mesoscutum, were brown. After two days, the median portion of the face and mandible (teeth, blackish brown) were yellowish white, femur yellowish brown, most of the first tergum (except apically reddish brown) were blackish brown, second and third terga yellowish brown with reddish marks. The body was black, antenna blackish brown, median portion of face and basal portion of mandible yellowish green, femora yellowish brown, second and third terga red when the pupa was mature (Fig. 15). Of 78 adults of Lamachus rufiabdominalis that emerged from cocoons of Neodiprion huizeensis , the female to male ratio was 2.1:1. The parasitism rates of Neodiprion huizeensis by Lamachus rufiabdominalis were 1.2% to 1.3%. Adults of Lamachus rufiabdominalis emerged between 3rd and 30th March under laboratory conditions.