Comprehensive Description

provided by Smithsonian Contributions to Zoology
Analysson rufescens

This nyssonid is readily distinguished in the Ceylonese fauna by a combination of the petiolate second submarginal cell, the single midtibial spur, the red color of the female thorax posteriorly, the trilobate median lobe of the labrum (Figure 16), the truncate apical margin of the clypeus, and the characteristic sculpture of the dorsal and posterior propodeal surfaces (Figure 4).

The species is widely distributed in Sri Lanka, primarily in the sandy areas of the more xeric parts, although it has been taken once on coarse sand along the bank of a river on the southwestern slope of the Adams Peak foothills. All specimens were taken at altitudes ranging from near sea level to about 150 m. The average annual rainfall ranged from 860–1075 mm in localities in the Dry Zone to some 3900 mm at Gilimale in the Wet Zone. The species occurs also in South India where it is known from two localities, one on the coast, the other inland at an altitude of 3100 ft.

ETYMOLOGY.—The species name is from the Latin rufesco (to become reddish).

HOLOTYPE.—; Sri Lanka, Uva Province, Monaragala District, Angunakolapelessa, 100 m, 21–23 Jan 1979, in Malaise trap, K.V. Krombein, P.B. Karunaratne, T. Wijesinhe, S. Siriwardane, T. Gunawardane (USNM).

FEMALE.—Length 7.0 mm. Black, the following light red: scutellum, metanotum, narrow posterior stripe on mesopleuron, metapleuron, propodeum, hind coxa and trochanter, extreme base of hind femur, apical segment of fore tarsus, and first abdominal segment except apical third of tergum; the following white: basal half of mandible, labrum, clypeus except narrowly at base, elongate subtriangular mark along inner eye margin from clypeus halfway to anterior ocellus, scape except narrowly along outer surface, pedicel above, narrow streak above on basal half of first flagellar segment, most of venter of fore- and midcoxae, foretrochanter beneath, basal half of forefemur beneath, narrow stripe on anterior surface of foretibia, stripe on basal two thirds of outer surface of midtibia, basal third of hind tibia, and transverse lateral oval spot near base of second tergum. Wings clear except forewing with infumated fascia extending across marginal cell, second and third submarginal cells, and outer half of third discoidal cell to posterior margin of wing; stigma black, veins dark brown. Vestiture: short, silvery, subappressed, moderately dense on side of clypeus, front, vertex, temples, pronotum, scutum, and mesopleuron; basal half of mandible and middle of clypeus with some long, suberect silvery setae; red areas of thorax with cinereous, subappressed, moderately dense, short setae; sides of abdominal terga I–II with scattered, long, suberect pale setae, terga III-V with suberect cinereous setae, longer and sparser on apical half, denser and shorter on basal half of exposed area; pygidium with dense, relatively short, erect brown setae on basal half, apical third with dense, appressed, reddish golden vestiture. Wings clear with a subapical infumation extending across marginal and outer two submarginal cells, broadening and weakening toward posterior margin; stigma and veins dark brown.

Clypeus and labrum (Figure 16); eyes diverging moderately above, interocular distance at anterior ocellus 1.2 times that at base of clypeus; front with close punctures separated by much less than half the diameter of a puncture; most punctures on vertex separated by about the diameter of a puncture; ocelli in a low triangle, postocellar distance 0.7 times ocellocular and ocelloccipital distances.

Pronotal disk and scutum with subconfluent punctures slightly larger than those on head; side of pronotum closely punctate except on lower third, with weak oblique rugulae above, becoming stronger on lower third; mesopleuron with close fine punctures behind omaulus, a few short longitudinal rugulae behind omaulus; metapleuron with close small punctures on upper third and scattered micropunctures on lower two-thirds; dorsal and posterior propodeal surfaces (Figure 4), rugae weaker than in most Alysson, enclosure short, without a pair of central, slightly divergent carinae as in Alysson, rugae longitudinal behind enclosure, oblique on either side of it, posterior surface with median carina and weak, mostly transverse rugulae.

ALLOTYPE.—; same label data as holotype but not in Malaise trap (USNM).

MALE.—Length 5.3 mm. Black, the following white: basal half of mandible, labrum, broad stripe on side of front extending from clypeus halfway to anterior ocellus, scape beneath, fore- and midcoxae beneath, small spot at apex of hind coxa beneath, streak on basal half of forefemur, streak on outer surface of foretibia, similar streaks on basal half of mid- and hind tibiae, and round anterolateral spot on second tergum; the following light red: most of hind coxa, trochanters, most of forefemur, mid- and hind femora, and tibiae beneath. Wings and vestiture much as in holotype.

Clypeus and labrum as in female (Figure 16); interocular distance at anterior ocellus 1.3 times that at base of clypeus; front more delicately punctate than in female, most punctures separated by about the diameter of a puncture; vertexal punctures smaller and more separated; postocellar distance 0.7 times ocellocular distance and 0.8 times ocelloccipital distance; flagellar segments II–X with a row of long setae beneath (Figures 24, 25), terminal segment larger than in Alysson, emarginate beneath (cf. Figures 23, 26).

Punctures on pronotal disk and scutum less dense than in female, ranging from subconfluent to separated by about half the diameter of a puncture; rugulae present only on lower third of side of pronotum, lacking on mesopleuron; propodeal sculpture similar to that of female.

Pygidial area delimited by a lateral carina on apical third of seventh tergum; genitalia of paratype (Figure 2).

PARATYPES (USNM except as noted).—7, 3, same data as holotype, 6, 2 in Malaise trap. NORTHERN PROVINCE, Mannar District: 4, 3, Silavathurai, Kondachchi, 22–28, 23–27, 24 and 25 Jan 1978, 2 in Malaise trap, P.B. Karunaratne, T. Wijesinhe, M. Jayaweera, G. Ratnavira (USNM, Colombo). 3, 0.5 mi (0.8 km) NE Kokmotte Bungalow, Wilpattu National Park, 15, 16 Feb 1979, 2 in Malaise trap, K.V. Krombein, T. Wijesinhe, S. Siriwardane, T. Gunawardane. NORTH CENTRAL PROVINCE, Anuradhapura District: 1, Wildlife Society Bungalow, Hunuwilagama, nr Wilpattu National Park, 200 ft (60 m), 10–19 Mar 1970, Davis & Rowe. SABARAGAMUWA PROVINCE, Ratnapura District: 1, Gilimale, Induruwa Jungle, 5–7 Feb 1977, K.V. Krombein, P. Fernando, D.W. Balasooriya, V. Gunawardane. SOUTHERN PROVINCE, Hambantota District: 1, 1, Palatupana Tank, 15–50 ft (5–15 m) 18–20 Jan 1979, in Malaise trap, K.V. Krombein, P.B. Karunaratne, T. Wijesinhe, S. Siriwardane, T. Gunawardane. SOUTH INDIA: 1, 1, Coimbatore, Dec 1951 () and Aug 1953 (), P.S. Nathan (Corvallis); 1, Ammatti, S(outh) Coorg, 3100 ft (945 m), Nov 1952, P.S. Nathan (Corvallis). A pair of paratypes from Sri Lanka has been deposited in the Colombo Museum, California Academy of Sciences, and in the British Museum (Natural History).

Female paratypes are 6.8–7.6 mm long, and males are 4.8–6.1 mm. There is very little variation in color or punctation.

Two species of Alysson are endemic in Sri Lanka, the very rare A. ruficollis Cameron, and the rather common A. triangularis, new species.
bibliographic citation
Krombein, Karl V. 1985. "Biosystematic Studies of Ceylonese Wasps, XV: A Monograph of the Alyssoninae, Nyssoninae and Gorytinae (Hymenoptera: Sphecoidea: Nyssonidae)." Smithsonian Contributions to Zoology. 1-43. https://doi.org/10.5479/si.00810282.414