The buccal cone projects antero-ventrally from the head and is formed from the distal borders of the labrum and labium united basally on the cone by the oral folds (Folsom, 1900). (Figs. 1
). The lateral free margins of the labrum are folded and thickened with smooth cuticle and converge towards the distal border where they end abruptly in an upturned collar-like structure (Fig. 1
). The general tuberculate cuticle of the body is continued on to the base of the labrum. A series of longitudinally arranged folds of finely granular cuticle run forward on the labrum merging to a single fold at the distal border (Fig. 1
). The page 3
Fig. 1 Ceratrimeria leleupi
Dorsal view of open buccal cone, showing mandibles protruding beyond edge of labrum and divided labium to right and left. The rod-like maxillae show partially at upper left, and the superlinguae appear at the distal border of the labrum. Note the folded, thickened, non-tuberculate edge of the labrum. Lb, labrum; Lm, labium; M, mandible; Mx, maxilla, (× 1,200).
Fig. 2 Ceratrimeria leleupi
Ventral view of open buccal cone. Superlinguae show beneath labium in upper centre of cone and a rod-like maxilla emerges from right of cone. Mandibles are partially obscured distal to superlinguae. Note deeply cleft labium with thickened folded borders, antenna above and at lower right. Sl, superlinguae; Lm, labium; Mx, maxilla; (× 600).
labium tapers distally on the cone in a similar manner to the labrum and is divided medially into right and left halves (Fig. 2
). The lateral and terminal borders, and distal portion of the medial borders are folded and thickened with smooth cuticle. From the medial division on the cone, the ventral line continues back the entire length of the labium to the thorax. The cuticle of the labium is tuberculate but in the distal half of the cone it is finely granulate and thrown into a number of irregular folds. Each half of the labial section of the cone carries a small basal seta and nine larger setae distal to this, one of which, situated near the basal seta is distinctly longer than the rest. The mouth opening at the apex of the cone extends down each side of the cone bordered by the thickened and folded margins of the labrum and labium. The mandible is a slender, elongated, rod-like structure with an expanded apical region which resembles a claw or scoop (Figs. 3
). Six strongly curved teeth of varying size are arranged at the apex and along the medial border. They consist of four major teeth with a small tooth between the first and second and another between the second and third major teeth. The basal or sixth tooth, is the longest and stoutest of all. The lateral border of the mandibular head is thickened and together with the apical tooth, is rolled slightly inward. The toothed border of the mandible is also rolled over in such a manner that an elongated cupped depression is formed between them, and the whole mandible head resembles a claw. The mandibular head is approximately 80 in length and 20 μm in its widest part. Each maxilla consists of a pair of slender rods or lamellae. In all specimens examined the rods were closely opposed (Fig. 3
), one of the pair being slightly longer than the other and faintly hooked apically. The maxilla is approximately 10 μm in diameter distally. The maxillae when exserted usually extend slightly beyond the mandibles. No opening could be found at the distal extremity of the maxilla to suggest a chemoreceptor function. The superlinguae are a pair of large, lamellate, folded structures lying between the labrum and labium. They appear to be situated ventrally to the mandibles and maxillae and may be partly exserted from the mouth opening (Fig. 1