Bembix tranquebarica (Gmelin 1790)

Bembix tranquebarica (Gmelin)

Bembex [sic] repanda Fabricius, 1787:286 [; Tranquebar; syntypes in Copenhagen].—Olivier, 1789:291 [brief description].—Fabricius, 1793:250 [brief description]; 1804:225 [brief description].—Jurine, 1807:175 [listed].—Dahlbom, 1845:487 [in key].—Handlirsch, 1893:896, 897 [copied original description].

Vespa (Bembyx [sic]) Tranquebarica [sic] Gmelin, 1790:2769 [new name for repanda Fabricius, preoccupied in Vespa by Crabro repanda Fabricius, 1787, also placed in Vespa by Gmelin, 1790:2761].

Bembex [sic] trepanda Dahlbom, 1844:181, 182 [, ; India; syntypes in Lund University].—Smith, 1856:328 [listed].—Bingham, 1896:445 [Ceylon locality].—Handlirsch, 1893:736, pl. 1: fig. 17, pl. 5: fig. 20, pl. 6: fig. 15 [India, Ceylon, Mauritius; redescription]; 1895:1051 [listed].—Bingham, 1897:288 [described].—Dalla Torre, 1897:515 [listed].—Rahman, 1940:430 [flower visits, prey].

Bembix trepanda Dahlbom.—Parker, 1929:101, figs. 207–209 [described].

Bembix repanda Fabricius.—van der Vecht, 1961:60, 61 [lectotype designation; placed tranquebarica and trepanda in synonymy].

Bembix tranquebarica (Gmelin).—Bohart and Menke, 1976:548 [listed repanda and trepanda as synonyms].

This species is very similar to orientalis. Specimens of tranquebarica from Sri Lanka and southern India are separated readily by the characters noted under orientalis.

MALE.—Length 14.5–15.5 mm, forewing 10–11 mm, wing index 1.70; mandible (Figure 25b) relatively slender, slightly curved toward apex, without cutting edge on inner margin beyond subapical tooth, index 1.9; clypeus 1.86 times as wide as high, somewhat flattened apically in middle; least interocular distance about a third distance from antennal sockets to anterior ocellus, 0.52 times eye height; center of vertex as high as top of eyes; scape 2.5 times as long as wide; first flagellar segment 2.6 times as long as wide; flagellar segments 5–10 widened, in profile 5–8 tuberculate, 9–10 lobate, 11 concave and truncate at tip, 4–6 with small sensory areas beneath at apex, 7–11 concave beneath, sensory areas covering entire venter; forefemur widened at middle, 2.6 times as long as greatest width, flattened beneath and with sharp posterior margin; forebasitarsus 3.7 times as long as wide, with 7–8 pecten spines, all but first quite stout; first four segments of foretarsus beneath with median tooth at apex, teeth becoming weaker on successive segments; midfemur with many small serrations beneath, not sharply edged; apex of midtibia produced into short spine adjacent to spur; tergum 7 emarginate at apex, lateral margin angulately emarginate at middle, posterior section forming a projecting lobe and depressed below anterolateral margin at angulation; sternum 2 with median process well developed, relatively stout, not strongly raised; median process of 6 triangularly raised, tapering to a narrow angle near apical margin; genitalia (Figures 11, 12).

Color: black, head and thorax with yellow markings, abdomen mostly white but terga yellow laterally and sterna apically, pale markings as follows: mandible except apical fourth, labrum, clypeus, front except pair of small triangular spots between antennal sockets and black ocellar triangle, broad stripe laterad of ocellar triangle extending almost to occipital margin, band along posterior orbit narrowing above to top of eye, scape except apical blotch above, flagellum beneath, pronotum except pair of small spots anteriorly on collar, scutum with median U-shaped mark and lateral stripe, both extending to near base, apical third of scutellum broadened laterally, apical half of metanotum, side of thorax except mesopleuron with small blotch adjacent to pronotal lobe and occasionally a small one posterolaterally, propodeal triangle except narrow basal band and small apical spot, lateral propodeum except small spot behind spiracle, posterior propodeum except broad V-shaped band margining triangle, most of legs except small spots on coxae and trochanters, apical blotch above on fore- and midfemora, apical stripe behind on hind femur, narrow basal stripe above and below on foretibia, narrow stripe above on hind tibia, small median spot beneath on forebasitarsus, tergum 1 with broad band on basal horizontal half or more enclosing, or almost so, a pair of round black spots anteriorly, 2 and 3 with broad basal bands enclosing a pair of transverse oval spots, 4 and 5 with broad bands shallowly biemarginate anteriorly and narrowed in middle posteriorly, broad lateral spots on 6 that may meet anteriorly, 7 with pair of small apicolateral spots, sterna 1–5 except narrow streak on process of 2, or 2 also with pair of small spots near process, 4 and 5 with large lateral spots, and 6 with large or small apicolateral spot. Wings hyaline; dense pale erect vestiture, long on front, vertex and gena, shorter on thorax and base of tergum 1, quite short on apex of 1 and 2–6.

FEMALE.—Length 9.5–14.5 mm, forewing 7.5–10.3 mm, wing index 1.68; mandible (Figure 25a) relatively slender, curved on apical third, slight cutting edge on inner margin beyond subapical tooth, index 2.1; clypeus 2.04 times as wide as high; least interocular distance halfway between antennal sockets and anterior ocellus, 0.57 times eye height; center of vertex as high as top of eyes; scape 2.9 times as long as wide; 1st flagellar segment 3.4 times as long as wide; forebasitarsus 3.1 times as long as wide, with 6–7 pecten spines; scutum with small subcontiguous punctures; sternum 2 with moderately large scattered punctures medially, punctures smaller laterally and separated by less than diameter of a puncture; margin of tergum 6 narrowly rounded at apex, apical rim smooth, otherwise with moderately large dense punctures.

Coloration similar to that of male except white markings present only on mandible, labrum, clypeus, and front, otherwise yellow; foretibia yellow above, forebasitarsus yellow, pygidium with pair of yellow spots, sternum 2 with large median black spot, 3–5 with large basal black spots. Wings and vestiture as in male.

VARIATION.—The descriptions of coloration above are of specimens from southern India. Three females from Deesa, Rajasthan in the Thar Desert have more extensive yellow markings and it is expected that males from such desert areas will be similarly colored. The black areas on head are reduced in extent, pronotum entirely yellow, U and lateral stripes on scutum broader and extending to base, markings on scutellum and metanotum broader, propodeum may be entirely yellow except base of triangle narrowly and tiny spot behind spiracle, bands on terga 1–3 correspondingly broader, each enclosing a pair of spots, bands on 4–5 broader, 6 may be yellow except narrow median and lateral lines and apex, sterna 1–5 may be entirely yellow, and 6 may be yellow except narrow median line and apical spot.

LOCALITIES AND MONTHS OF COLLECTION (USNM unless indicated otherwise).—Sri Lanka, NORTH CENTRAL PROVINCE, Polonnaruwa District: Polonnaruwa (; Basel). EASTERN PROVINCE, Amparai District: Pottuvil (; Basel).

India, Madras: Coimbatore (2; Sep; Corvallis); Karikal (; May, Corvallis), Kurumbagaram (2; Mar, Aug), Tranquebar (9,; Feb, Mar, Jul, Corvallis). Rajasthan: Deesa (3; Apr, Oct).

Bembix tranquebarica (Gmelin)

We did not collect this species in Sri Lanka, but Rahman (1940:430) noted at Lyallpur, Pakistan, that it visited flowers of toria and sarson (cultivated varieties of Brassica), nested in the ground, and provisioned progressively with unspecified species of Syrphidae, Muscidae, and Calliphoridae. He gave no details of nest architecture. He concluded that the species was “an undesirable visitor to toria and sarson flowers,” presumably because it included Syrphidae, an important pollinator, among its prey.