Syzeuctus FÖRSTER, 1868

Riedel, Matthias, 2022, Contribution to the knowledge of Oriental Syzeuctus FÖRSTER (Hymenoptera, Ichneumonidae, Banchinae), with description of six new species, Linzer biologische Beiträge 54 (1), pp. 257-273 : 271-272

Key to the ♀♀ of the Oriental species of Syzeuctus FÖRSTER

adopted from CHANDRA & GUPTA (1977) and NIKAM & KANHEKAR (1987)

1 Metasomal spiracles strongly enlarged and specialized. Propodeum yellow, with long black mark below spiracle and a pair of submedian basal black marks. ............................... .............................................................................................................. claripennis group: 2

- Metasomal spiracles not enlarged and specialized. Propodeum various. ............................3

2 Specialized spiracles roundish, located on the 3 rd and following tergites. Fore and mid trochanters and femora blackish dorsally. Hind tarsus ochreous. India, Sri Lanka. .............. .......................................................................................... S. claripennis (CAMERON, 1902)

- Specialized spiracles elliptic and located on the 1 st to 4 th tergites. Fore and mid trochanters and femora entirely yellow. Hind tarsus blackish-brown. Philippines................ ...................................................................................... S. macrospiracularis MOMOI, 1971

3 Metasoma reddish or red with black markings ( fig. 2 ). Fore and mid femora often with black dorsal lines........................................................................................ villosus group: 4

- Metasoma black, apical margins and sometimes also basal bands yellow ( figs 1, 3 ). Fore and mid femora usually without black lines, rarely mid femur black dorsally.............. ............................................................................................................... zanthorius group: 9

4 Apical transverse carina of propodeum complete................................................................5

- Apical transverse carina of propodeum medially or completely absent. .............................6

5 Ovipositor shorter than metasoma, 1.2× longer than hind tibia. Mesosoma covered with long setae. Fore and mid coxae and trochanters black; fore coxa and trochanter frontally yellow. Metasoma red; 1 st tergite apically and 2 nd tergite basally blackish. India........................................................................................ S. villosus (CAMERON, 1899)

- Ovipositor longer than metasoma, 2.5× longer than hind tibia. Mesosoma covered with shorter setae. Fore and mid coxae and trochanters cream-yellow. Metasoma red; 1 st tergite yellow basally and apically ( fig. 4 ). Indonesia: Sulawesi ........................................... ........................................................................................................... S. achterbergi nov.sp.

6 Ovipositor about as long as metasoma ( fig. 2 ). Mesosoma entirely black. Coxae and trochanters black, fore coxa entirely and spot on mid coxa yellow. Basal tergites dark reddish ( fig. 9 ). Thailand....................................................................... S. siamensis nov.sp.

- Ovipositor distinctly longer than metasoma. Mesosoma with ± extended yellow coloration ( figs 1, 3 ). Coxae and trochanters yellow, with black markings.........................7

7 4 th to 7 th tergites entirely red; 1 st to 3 rd tergites black, with apical yellow bands; 2 nd and 3 rd tergites reddish centrally ( fig. 5 ). Flores. ...................................... S. floresiensis nov.sp.

- Metasoma red, all tergites apically and 1 st tergite basally yellowish. ..................................8

8 Mesoscutum, mesopleuron and propodeum entirely black. Vein 1cu-a interstitial. Body small and slender. India..................................................... S. apicipennis (CAMERON, 1902)

- Mesoscutum black, with large median yellow spot confluent with antero-lateral yellow marks. Mesopleuron and propodeum largely yellow. Vein 1cu-a postfurcal. Body larger and stouter. Pakistan. ...................................... S. baluchistanensis (CAMERON, 1906)

9 Apical transverse carina of propodeum incomplete medially or absent. ...........................10

- Apical transverse carina of propodeum complete. Mesopleuron and propodeum entirely punctate.. ...........................................................................................................................12

10 Apical transverse carina of propodeum absent, indicated by an obtuse ridge. MI 1.0. Dorsal half of mesopleuron and dorso-median part of propodeum unsculptured. Fore wing not infuscate apically. Hind claw simple. Philippines. ................................................. .................................................................................................. S. torrevillasi MOMOI, 1971

- Apical transverse carina of propodeum present laterally, absent medially. MI 0.6-0.8. Propodeum and mesopleuron densely punctate. Fore wing ± infuscate apically. Hind claw sometimes pectinate..................................................................................................11

11 Ovipositor 1.25× longer than fore wing. Hind femur black, with narrow yellow apical band ( fig. 1 ). Hind claw simple. Laos. ..................................................... S. laoticus nov.sp.

- Ovipositor 0.7-0.9× as long as fore wing. Hind femur red, ± yellowish medially. Hind claw with basal teeth. India. ...................................... S. indicus NIKAM & KANHEKAR, 1987

12 Ovipositor shorter than metasoma. Hind claw simple. Java. ................................................. .......................................................................................... S. incompletus SZÉPLIGETI, 1908

- Ovipositor at least as long as metasoma. Hind claw pectinate. .........................................13

13 Propodeum with distinct pleural carina. 2 nd and 3 rd tergites black medially, red or ochreous basally, yellowish apically. Flagellum with 44-48 flagellomeres.......................14

- Propodeum without pleural carina. 2 nd and 3 rd tergites black, yellow basally and/or apically. Flagellum with 27-48 flagellomeres. ..................................................................15

14 Clypeus smooth apically. Epicnemial carina ending near lower hind corner of pronotum. Speculum smooth. Fore wing with brown spot apically. 1 st tergite basally and apically yellow. Widespread in Oriental region.............................................................. ............................................................................ S. immedicatus CHANDRA & GUPTA, 1977

- Clypeus finely punctate. Epicnemial carina ending at center of mesopleuron. Speculum punctate. Fore wing hyaline, not distinctly infuscate apically. 1 st tergite subbasally with lateral cream-yellow marks and apical cream-yellow band. India......................................... ............................................................................... S. nagzirae NIKAM & KANHEKAR, 1987

15 Ovipositor 1.7× longer than fore wing and 4.0× longer than hind tibia. All tergites smooth and shining, with small scattered punctures. 6 th to 8 th tergites without yellow apical margins. Hind coxa and trochanter entirely reddish. India.......................................... ........................................................................ S. leptopunctatus CHANDRA & GUPTA, 1977

- Ovipositor at most as long as fore wing. Hind coxa black, yellowish apically. Hind trochanter black. Tergites except 1 st tergite densely punctate, all tergites with yellow apical bands. .....................................................................................................................16

16 Malar space long, 1.0× as long as width of mandibular base ( fig. 12 ). Flagellum with 42 flagellomeres. Hind femur yellow. 1 st tergite 1.6× longer than wide. Ovipositor 2.3× longer than hind tibia. Vietnam. ............................................................... S. genator nov.sp.

- Malar space shorter, 0.4-0.6× as long as width of mandibular base (as fig. 14 ). Flagellum with 37-40 flagellomeres. Hind femur red. 1 st tergite 1.7-2.3× longer than wide. Ovipositor 2.6-2.8× longer than hind tibia. India, Myanmar. ...................................... ............................................................................................ S. zanthorius (CAMERON, 1902)

Figures

Figs 1-3: Habitus from dorsal: (1) Syzeuctus laoticus nov.sp. ♀ holotype (HT); (2) S. siamensis nov.sp. ♀ HT; (3) S. orientalis nov.sp. ♁ paratype (PT).

Figs 4-9: Basal tergites from dorsal: (4) Syzeuctus achterbergi nov.sp. ♀ HT; (5) S. floresiensis nov.sp. ♀ HT; (6) S. genator nov.sp. ♀ HT; (7) S. laoticus nov.sp. ♀ HT; (8) S. orientalis nov.sp. ♁ PT; (9) S. siamensis nov.sp. ♀ HT.

Figs 10-15: Faces from frontal: (10) Syzeuctus achterbergi nov.sp. ♀ HT; (11) S. floresiensis nov.sp. ♀ HT; (12) S. genator nov.sp. ♀ HT; (13) S. laoticus nov.sp. ♀ HT; (14) S. orientalis nov.sp. ♁ HT; (15) S. siamensis nov.sp. ♀ HT.