Serendibula insolita Krombein 1983

Serendibula insolita

The female of S. insolita is very like that of S. gracilis in having a more slender abdomen than that of S. karunaratnei, and in having the front protruding noticeably beyond the eyes instead of not protruding noticeably. The horizontal area of the first metasomal tergum in S. insolita has larger punctures, many of which are separated from each other by no more than twice the width of a puncture, whereas on this area in S. gracilis the tiny punctures are quite scattered. Also, the carinate area of the second tergum extends farther toward the apex laterally in S. insolita (0.71–0.78) than in S. gracilis (0.59–0.60).

The male of S. insolita differs from that of S. gracilis in having some of the contiguous punctures on the pronotal disk arranged in oblique or arcuate rows. It differs from males of S. deraniyagalai and S. karunaratnei in having the metasoma relatively narrower, the width at juncture of first and second terga 2.49 times the length of the first and 1.47 times the length of the second, rather than 2.85 times the length of the first and 1.59 times the length of the second.

The species is known only from two females and one male from the Badegamuwa Jungle, Kurunegala, in the Wet Zone where the average annual rainfall is 2075 mm.

ETYMOLOGY.—The specific name is based on the Latin insolitus (unusual).

HOLOTYPE.— Sri Lanka, North Western Province, Kurunegala District, Kurunegala, Badegamuwa Jungle, in or on leaf litter, 14–15 Mar 1981, K.V. Krombein, T. Wijesinhe, L. Weeratunge (USNM Type 100449).

FEMALE.—Length 3.8 mm. Black and shining, except top of head and thoracic dorsum dull from close punctation; mandible except tip, apex of malar space, thorax except middle of scutum, and tarsi beneath light red; scape beneath and tarsi above medium brown; apical half of fore and mid-coxae beneath, hind coxa beneath and trochanters pallid white; extreme bases of mid- and hind femora and of all tibiae stramineous. Vestiture black except white on front, eyes, sides of last three metasomal terga and sterna.

Head as in S. deraniyagalai except viewed from above, front protrudes noticeably beyond eyes.

Thorax as in S. deraniyagalai except median length of pronotal dorsum 2.0 times combined lengths of scutum and scutellum which are equal in length; combined lengths of latter two sclerites 0.9 times length of postscutellum; enclosed triangular area of postscutellum 1.4 times basal width.

Metasoma slender (Figure 63), the first tergum with length 0.78 times apical width, dorsal area with relatively large punctures, many of them separated by not more than twice the width of a puncture; carinate basal area of second tergum 0.3 times as wide as length along midline and extending over lateral four-fifths.

ALLOTYPE.— same locality, date and collectors as holotype (USNM).

MALE.—Length 3.5 mm. Black; head and thorax somewhat dull from coarse punctation but interspaces shining as is abdomen; scape beneath, fore tibia beneath, and declivous surface of first metasomal segment, medium red; rest of fore tibia, mid-tibia, base of hind tibia, and fore tarsus brown; mid-tarsus stramineous. Erect vestiture shorter than in female, whitish except brown on flagellum. Wings clear, costa and stigma medium brown, other veins light brown.

Head width 1.2 times distance from clypeal apex to posterior ocelli; malar groove distinct; frontal concavity shallow, transversely rugulose, median ridge lacking; viewed from above the front protuding somewhat beyond eyes; interocular distance at anterior ocellus 0.4 times head width; ocular microtrichiae shorter than in female.

Pronotum with median groove on posterior two-thirds, punctures contiguous, some of them arranged in arcuate rows, 0.9 times as long as scutum; scutum with shallower contiguous punctures but equal in size to those on pronotal disk, not arranged in transverse rows, 1.1 times as long as combined lengths of scutellum and postscutellum, the latter two equally long; scutellar punctures more separated in middle than on scutum but contiguous at sides; U-shaped area of postscutellum 1.6 times as long as basal width, with sparse shallow punctures and flanked laterally by short oblique rugulae; mesopleuron with large, shallow, mostly subcontiguous pits, but anteriorly some separated by half the width of a puncture; lateral surface of propodeum glossy, posterior surface closely, irregularly rugulosoreticulate.

Metasoma relatively slender, width at juncture of first and second terga 2.5 times length of first and 1.5 times length of second; declivous surface of first tergum glossy and smooth; dorsum of first tergum, and second tergum and sternum with small punctures mostly separated by half the width of a puncture; digitus as long as aedeagus.

PARATYPE.—1, same label data as holotype (USNM). It will be deposited in the Colombo Museum.

The paratype also is 3.8 mm long and differs from the holotype as follows: thorax entirely light red; median length of pronotal dorsum 1.8 times combined lengths of scutum and scutellum; scutum 1.25 times as long as scutellum, and combined lengths of these sclerites 1.1 times as long as postscutellum; enclosed triangular area of postscutellum 1.3 times basal width; and first metasomal tergum with median length 0.71 times apical width, apically with a few short longitudinal striae.