Bembix lunata Fabricius 1793

Bembix lunata Fabricius

Bembex [sic] lunata Fabricius, 1793:249 [, Tranquebar; syntypes in Copenhagen]; 1804:224 [brief description].—Jurine, 1807:175 [listed].—Dahlbom, 1845:492 [ in key].—Smith, 1856:328 [listed],—Handlirsch, 1893:777, 778 [redescribed]; 1895:1054 [listed].—Bingham, 1897:285, 286, pl. 2: fig. 4 [redescribed].—Dalla Torre, 1897:507 [listed].—Ayyar, 1919:909, 910, pl. 141 [prey].

Bembix lunata Fabricius.—van der Vecht, 1961:59, 60 [lectotype designation].—Bohart and Menke, 1976:547 [listed].

Bembix lunata is the only Ceylonese and South Indian representative of the small bidentata Group. It is unique in that group, and also in this fauna because of its predominantly light red ground color and the presence in the male of a short spine on the inner ventral angle of the midcoxa.

MALE.—Length 14.2–18.5 mm, forewing 11.0–14.0 mm, wing index 1.87. Mandible (Figure 27b) stout, slightly curved toward tip with large cutting edge beyond tooth, index 1.66; clypeus 1.81 times as wide as high, slightly flattened below basal keel; least interocular distance about halfway between antennal sockets and foreocellus, 0.56 times eye height; center of vertex slightly below top of eye; scape 1.9 times as long as wide; first flagellar segment 3.8 times as long as wide; terminal flagellar segments less modified than in other species, 6–10 somewhat widened, in profile 7–8 slightly dentate and 11 concave, 6–11 with concave sensory areas beneath, that of 6 small and apical, those of 7–11 increasing in size toward tip and covering most of surface; forebasitarsus 4.2 times as long as wide, bearing 7 pecten spines; midcoxa with short acute spine at inner ventral angle; midfemur beneath on apical half with sharp teeth along posterior margin; tergum 7 rounded apically; sternum 2 without median process, a median strip smooth, laterad of that with rather scattered small punctures gradually becoming denser toward side and separated by width of a puncture; sternum 6 convex, occasionally slightly raised in middle.

Ground color predominantly light red but black on head, apical three or four flagellar segments, pronotum, scutum except normal yellow markings light red, sides of meso- and metapleura, mesosternum except red at apex, and propodeum; pale markings white on clypeus, front and propodeal dorsum, otherwise yellow, as follows: mandible except apical third, labrum, clypeus, median triangular spot above clypeus, lateral stripe on front shading to light red opposite ocellar triangle, pair of small median spots below anterior ocellus, elongate triangular spot along outer orbit sometimes shading to light red near top of eye, pronotum except median anterior bar, normal U-shaped mark on scutum red, tiny posterolateral spot or stripe on scutum, mesopleuron except behind pronotal lobe and small area ventrally, mesepimeron usually red but occasionally yellow above, metapleuron, propodeal triangle with a broad V-shaped mark across middle, posterior and lateral surfaces except a broad V-shaped mark from abdominal attachment extending upward toward spiracle, forecoxa, mid- and hind coxae except most of ventral surface, trochanters, forefemur except narrow black streak on basal half posteriorly, midfemur, hind femur except beneath, tibiae and tarsi, pair of triangular spots on tergum 1 usually well separated in middle but occasionally almost touching, paired sublunate spots on 2–4 narrowly separated at midline, those on 4 sometimes joined, broad band over most of 5 biemarginate anteriorly, 6 at apex with or without narrow band or small median spot, 7 with apical spot, sterna 2–5 with posterolateral triangular spots connected by narrow apical band and 6 with apical band. Wings hyaline but stained with light brown along some veins; vestiture dense, pale, erect on front, vertex, gena, thorax, and base of tergum 1, short, suberect and with yellowish cast on remainder of terga, sterna with sparse subdecumbent setae except 5 and 6 with dense longer erect yellowish setae.

FEMALE.—Length 14.0–19.3 mm, forewing 10.6–15.0 mm, index 1.97. Mandible (Figure 27a) stout, curved on apical third, inner margin with large cutting edge beyond subbasal tooth, index 2.29; clypeus 1.88 times as wide as high, flattened in middle beyond basal keel; least interocular distance midway between antennal insertions and anterior ocellus, 0.60 times eye height; vertex slightly below top of eyes; scape 2.2 times as long as wide; first flagellar segment 4.5 times as long as wide; forebasitarsus 3.5 times as long as wide, with 7 pecten spines; scutum with small subcontiguous punctures; sternum 2 with narrow smooth median area on basal half, laterad of this with a narrow area bearing larger scattered punctures and on sides with smaller punctures mostly separated by about a puncture's width; tergum 6 narrowly rounded apically, with close small punctures.

Color similar to that of male but ground color entirely light red except black are apex of mandible, ocellar area, narrow base of scutum in middle, posterolateral mark or stripe on scutum, narrow basal stripe on propodeal triangle, narrow V-shaped line or stripe margining triangle, spot behind spiracle; pale markings entirely yellow and as in male except clypeus not entirely yellow but red on base, tergum 4 always with an anteriorly biemarginate band, and band on 5 sometimes divided into three spots. Wings and vestiture as in male except clypeus with two areas of appressed silvery setae, not so dense nor conspicuous as in borrei.

LOCALITIES AND MONTHS OF COLLECTION (USNM unless indicated otherwise).—Sri Lanka, NORTH CENTRAL PROVINCE, Polonnaruwa District: Polonnaruwa ( Basel). EASTERN PROVINCE, Trincomalee District: Kantalai (2 Aug; Colombo). SOUTHERN PROVINCE, Hambantota District: Katagamuwa (, Sep; Colombo).

India, Madras: Karikal ( May; Corvallis), Kurumbagaram (7 Mar), Nilgiri Hills, Singara, 3400 ft ( May; Corvallis), Puttuchcheri, Karaikkal (2, 2 Feb, Mar; Leiden).

Bembix lunata Fabricius

We did not collect this species in Sri Lanka, but Ayyar (1919) listed some prey records in India. He found it at Hillgrove, Nilgiri Hills, 2000 ft, preying upon Stomoxys, Haematobia (recorded as Lyperosia), and Musca (recorded as Philaematomyia), all biting species of Muscidae that were attacking a cow. He also noted lunata preying on the same flies attacking cart bullocks in Thanjavur (= Tanjore).

The mandibles of our females are quite eroded, to or a bit beyond the cutting edge on the inner surface and the subbasal tooth, suggesting that lunata may nest in stony soil. Mandibles of males do not exhibit the same degree of wear, so they may occupy the original resting burrow on subsequent nights once it has been dug.