Chalogaster spatulata, CARPENTER & STARR, 2000

CARPENTER, JAMES M. & STARR, CHRISTOPHER K., 2000, A New Genus of Hover Wasps from Southeast Asia (Hymenoptera: Vespidae; Stenogastrinae), American Museum Novitates 3291 (1), pp. 1-12 : 3-6

Chalogaster spatulata , new species

DIAGNOSIS: Among the characters given for the genus, the spatulate antennae, dilated midtarsi and the lobate parameral spines of the male will at once distinguish this species from other Stenogastrinae . Among characters listed below, the elongate third submarginal cell and single midtibial spur may also distinguish this species.

DESCRIPTION: Male. Forewing length 8.5– 9.2 mm. Head, including clypeus, moderately wider than long; clypeus with apex convex, roundly angled; frontoclypeal suture distinct, strong; antennal sockets far apart and separated from clypeus by long supraclypeal area; antennae with scape and pedicel roundly flattened; ocelli large, ratio of width to distance from eye about 0.7 for anterior ocellus and 1.4 for either posterior ocellus; pronotum lacking dorsal carina and pretegular carinae; parapsidal and admedian lines deeply impressed; scutellum lacking median carina; length of metanotum along midline about equal to that of scutellum; forewings with RS straight along posterior border of marginal cell, second submarginal cell rectangular, third submarginal cell elongate, nearly attaining wing apex. One of the paratypes has an adventitious marginal cell in the left wing. Hindwings with two closed cells; forefemora in dorsal view curving anteriorly; midtibiae with single spur; metasomal segment I about 1.5× the length of the mesosoma, apical bulb of segment I about three times as broad as main part of petiole, scarcely narrowed behind. The genitalia are illustrated in figure 7. Cuticle smooth and shining, appearing duller and more granulate on metasoma, clypeus with shallow, dense punctures, coarser on frons, forming weak striae, ventral angle of pronotum, notauli, dorsal groove of mesepisterna, median groove of propodeum crenulate, pronotum with striae anteriorly above, weak striae dorsally on metapleura and propodeum, dense striae anterodorsally on mesepisterna. Vestiture pale short hairs on clypeus, frons and mandible, denser on genae, longer more scattered hairs on vertex, dorsum of thorax, propodeum, and legs, denser on coxae and femora; mid­ and hindtibiae and tarsi with numerous very long, fine, erect hairs; very dense, short hairs on mesepisterna dorsally and posteriorly, metapleura and propodeum anteriorly; metasoma with scattered short hairs on terga and a few longer hairs on sterna. Coloration black; yellow are clypeus except for apex and a variably developed mark above the apex, solid or U­ to W­ shaped, broad stripes below antennal sockets, hind margin of pronotum entirely or posteriorly, and occasional spots or stripes at anterior margin and in ventral angle, short lines anteriorly along the notauli, tegulae variably, spots or most of scutellum, most of metanotum, large mesepisternal spot dorsally, occasionally small ventral spots, variably spots anterodorsal to propodeal spiracle and above orifice, variably developed hindcoxal spots, all femora at least apically, and mid­ and hindfemora sometimes mostly, midtibiae and stripes to much of fore­ and hindtibiae, midtarsi largely to at least basistarsi, sometimes foretarsi largely; pale whitish are the spatulate processes of the antennae apically, propleura, metasomal Tergum II basally or spots, Terga IV–VII each with a broad white basal band, conspicuous when the segments are even a little extended; brownish are the base of Tergum II–III, the sides of Terga II– VII, Sterna II–VII variably.

Female. Forewing length 9.2–9.4 mm. Clypeus with apex convex, sharply pointed; antennae moderately clavate, with tenth article less than twice as wide as fourth; mandibles tridentate; scutellum with carina weak but clear, developed only anteriorly; meso­ metapleural and thoracic­propodeal sutures subparallel; metasomal Tergum VI without spine. Cuticle generally as in male, but metasoma more shining, not appearing dull and granulate. Vestiture differs from the male in hairs generally longer and more abundant, but lacking dense pilosity on sides of thorax. Coloration differs from the male in the clypeus with only yellow stripes laterally, scutellum with small lateral spots, broad separated spots on metanotum, variable spots dorsally on propleura, broad ventrolateral stripes on mesepisterna, metapleura with dorsal spots, broad spots above propodeal orifice, legs with only stripes on coxae, tips of femora, foretibiae with stripes to mostly, foretarsi variably, metasoma with only small lateral stripes on Tergum I, base of Tergum II, basal spots on Tergum III; only Sternum II basally pale.

NEST, LARVA: Unknown.

TYPE MATERIAL: Holotype male from Viet Nam: Quang Binh Prov., Cha Lo, 17°42'N 105°46'E, 14–17 April 1998, 298 m (James M. Carpenter), in the Institute of Ecology and Biological Resources ( IEBR), Ha Noi; on long­term loan to the American Museum of Natural History ( AMNH) . Paratype female and four paratype males with the same data in the IEBR ; paratype female and four paratype males with the same data in the AMNH . Two more paratype males are from Thailand: Chieng Mai Prov., Doi Suthep, 1100 m, 2 October 1981, Zool. Museum Copenhagen leg. (Zoologisk Museum, Copenhagen); and Thailand: Loei Prov., Phu Luang, Wildlife Sanctuary, 8–14. October 1984, Karsholt, Lomholdt and Nielsen leg. ( National Museum of Natural History , Washington, DC) .

KNOWN DISTRIBUTION: Cha Lo , in the Truong Son Mountains of central Viet Nam (type locality), and northern Thailand (fig. 8). These three localities are not close to each other, so that Chalogaster spatulata may well be widespread in Indochina. There is no evident reason not to expect it in Laos and Cambodia, or even Yunnan .

ETYMOLOGY: The specific name refers to the remarkable terminal antennal article of the male.

REMARKS: Although the spatulate antennal flagellomere is a remarkable apomorphy, and unique in Stenogastrinae , even more striking spatulate modifications are found in the nomiine bee Spatunomia (Pauly, 1990: figs. 331– 332).