Cassidibracon gracillariae Quicke, 2012

Quicke, Donald L. J., Broad, Gavin R. & Butcher, Buntika Areekul, 2012, First host record for the Palaeotropical braconine wasp genus Cassidibracon Quicke (Hymenoptera, Braconidae) with the description of a new species from India, Journal of Hymenoptera Research 28, pp. 135-141 : 139-140

Cassidibracon gracillariae Quicke sp. n.

Material examined.

Holotype. Female, "19.vi.1911, Parasite on Epicephala chalybacma , Pusa [INDIA], C. S. Misra", “72” (BMNH)

Paratypes. 2 females, same data as holotype.

Diagnosis.

In Narendran et al.'s (1994) key to species, the new species runs to Cassidibracon sumodani Narendran because of its complete propodeal carina, but differs in having more (24 as opposed to 21) flagellomeres and in the dark pattern on the metasoma. The new species differs from all other known species of the genus in having a large ‘H’ -shaped black mark extending over tergites 2-4.

Narendran et al.'s (1994) key can be modified as follows to include the new species.

1	Propodeum with complete midlongitudinal carina. Body yellowish brown	2a
-	Propodeum with incomplete midlongitudinal carina. Body brown or blackish brown	3
2a	Metasoma entirely yellowish. Face with midlongitudinal ridge which is produced to form knob between antennal sockets [Afrotropical]	Cassidibracon castus
-	Metasoma with distinct pattern of dark marks. Face without midlongitudinal ridge [Oriental]	2b
2b	Antenna with 21 flagellomeres. Dark posterior marking on tergite 2 and anterior of tergite 4 entire	Cassidibracon sumodani
-	Antenna with 24 flagellomeres. Dark posterior marking on tergite 2 and anterior of tergite 4 completely divided medially by pale brown yellow zone giving rise to ‘H’ -shaped pattern	Cassidibracon gracillariae sp. n.

Description.

Length of body 2.9 mm, of forewing 2.6 mm and of antenna 2.8 mm.

Head. Antenna with 24 flagellomeres. Median flagellomeres approximately 1.4 × longer than wide. 1st flagellomere 1.1 × longer than both the 2nd and 3rd segments separately. Face shiny with numerous punctures at bases of setae. Height of eye: width of head: width of face = 1.0: 2.5 : 1.05. Intertentorial distance 1.7 × tentorio-ocular distance. POL: transverse diameter of posterior ocellus: shortest distance between posterior ocellus and eye = 1: 1 : 3.

Mesosoma. Mesosoma approximately 1.5 × longer than high. Midlongitudinal propodeal carina running within a deep, foveolate groove. Propodeum largely shiny, anteriorly smooth becoming distinctly weakly longitudinally striate medially merging to punctate sculpture posteriorly.

Wings. Fore wing vein cu-a marginally postfurcal. Lengths of fore wing veins r:3-SR:SR1 = 1.0: 1.7: 5.0.

Legs. Length of hind femur: tibia: tarsus = 1.2: 1.0: 1.0. Hind tibia 4.5 × longer than maximally deep.

Metasoma. Metasomal tergites irregularly densely punctulate. 2nd tergite 1.9 × wider than medially long. 3rd tergite 2.5 × wider than medially long.

Coloration. Antenna orange-brown becoming black on apical third. Head cream-yellow with stemmaticum black. Mesosoma largely cream-yellow with dark marks on lateral lobes and anterior of middle lobe of mesoscutum. Metasoma cream-coloured with large ‘H’ -shaped black mark extending over tergites 2-4.

Notes on biology.

The type series of Cassidibracon gracillariae sp. n. are labelled as having been reared from ' E [picephala]. chalybacma ' (now Stomphastis chalybacma (Meyrick, 1908)) ( Lepidoptera : Gracillariidae ). Specimens of Stomphastis chalybacma in BMNH share the highly distinctive cocoons and there is no doubt that the original host identification was correct. The host is a widespread moth in south-east Asia which mines leaves of Caesalpinia and Samanea species ( Fabaceae ). The gracillariid, which feeds solitarily as a leaf-miner, pupates in a flattened silken cocoon ornamented with a cluster of distinctive bubbles, excreted by the larva, along the whole length of the cocoon. These bubbles presumably serve a defensive (or camouflage) function and resemble an egg mass, or possibly a parasitoid cocoon mass. The ovipositing Cassidibracon presumably attacks either pre-pupal larva or pupal hosts.