Ceresium vacillans Dillon & Dillon, 1952

Waqa-Sakiti, Hilda, Winder, Linton & Lingafelter, Steven W., 2015, Review of the genus Ceresium Newman, 1842 (Coleoptera, Cerambycidae) in Fiji, ZooKeys 532, pp. 15-53 : 41-42

Taxon classification Animalia Coleoptera Cerambycidae

Ceresium vacillans Dillon & Dillon, 1952 Fig. 18

Ceresium vacillans : Dillon and Dillon 1952: 24, Fiji: Lau Islands, Thikombia, holotype (BPBM).

Description.

Based on the holotype specimen (BPBM) and a specimen from 1998 survey (USP). Size 9.0-13.0 mm long, 2.0-3.0 mm wide at humeri; integument color maroonish brown (Fig. 18a). Head with slightly deep interantennal tubercle region, tubercles only slightly raised; punctate with moderately dense yellow pubescence on tubercles and throughout frons; vertex and occiput bare. Distinct median line between eye lobes. Yellow pubescence denser around eye margins and basal head margin. Frons and frontoclypeal margin moderately dense and coarsely punctate with sparse, long, yellow hairs (Fig. 18b). Antennae long, extending beyond elytra by four antennomeres. Antennae with vestiture of short, dense, ochraceous setae. Antennomeres unspined and expanded at apices; last antennomere just slightly longer than penultimate. Scape shorter than all antennomeres; 5-7 very long and the longest and subequal in length. Scape short, clavate, extending to apical fifth of pronotum.

Pronotum arcuate, wider across middle, transverse, apical margin narrower than base. Disk moderately dense with ochraceous pubescence, and coarsely punctate. Medially with a broad transversely ovate impression limited by two low tubercles in front, two behind and a fifth one in its center (Fig. 18c). Elytron with irregularly disposed ochraceous pubescence with irregular, small, glabrous maculae. Punctation shallow, dense, gradually becoming shallower and indistinct towards apex. Elytral apex together rounded. Scutellum broadly rounded, covered with dense, ochraceous pubescence. Legs moderate in length, femora distinctly but gradually clavate, hind femora just reaching elytral apex.

Venter of abdomen with moderately dense, ochraceous pubescence at sides, sparse ochraceous pubescence along middle, except for prosternum which is sparsely pubescent throughout and on sides. Prosternal process broad, vertical and acutely declivous, about 1/4 width of procoxa, weakly notched and expanded at apex. Procoxal cavities open posteriorly (Fig. 18d). Mesocoxae closed laterally to mesepimeron. Mesosternal process broad, expanded at apex, inserted into mesocoxa. Mesosternum rather acutely declivous, with small anterior tubercle, and sulcate anteriorly. Apex of terminal ventrite truncate to unevenly rounded, without notch.

Remarks.

This species is most similar to Ceresium striatipenne in that it possesses glabrous regions on the elytra, however in this species, the glabrous regions are irregular and small rather than forming narrow lines as in Ceresium striatipenne . This species is endemic to Fiji and known only from Viti Levu and the Lau Islands where specimens have been collected in July and September ( Dillon and Dillon 1952).