Paedalgus termitolestes, Wheeler, W. M., 1922

Wheeler, W. M., 1922, The ants collected by the American Museum Congo Expedition., Bulletin of the American Museum of Natural History 45, pp. 39-269 : 177-180

Paedalgus termitolestes , new species

Plate XVI; Text Figures 42 and 43

Worker.- Length 1 mm.

Head subrectangular, a little longer than broad, nearly as broad in front as behind, with feebly rounded sides and feebly excavated posterior border. Eyes very small, situated at the anterior third of the head. Mandibles rather narrow, with four subequal teeth. Clypeus convex in the middle, bicarinate, with the anterior border projecting and truncated in the middle, narrow on the sides. Antennae robust, scapes reaching to the second third of the sides of the head; funicular joints 2 to 6 subequal, much broader than long, together but little longer than the first joint; basal joint of club slightly longer than broad, less than one-third as long as the apical, which is nearly as long as the remainder of the funiculus. Thorax narrower and somewhat shorter than the head, broad in front, narrowed in the epinotal region, with subangular humeri; its dorsal surface in profile straight and horizontal to the base of the sloping, very bluntly angular epinotum, without promesonotal and mesoepinotal sutures; the epinotal declivity on each side with a low, subtriangular, vesiculate lamina. Petiole with a short, stout peduncle, its node high, rounded, about one and one-half times as broad as long, transversely elliptical from above. Postpetiole smaller than the petiole, its node much lower, only a little broader, a little less than twice as broad as long. Caster elliptical, its anterior border concave in the middle. Legs rather short.

Head, thorax, petiole, and postpetiole opaque, covered with shallow, saucershaped punctures, arranged in regular rows on the head and each bearing in its center a short hair. Upper surfaces of petiolar and postpetiolar nodes smoother and somewhat shining. Gaster and legs very smooth and shining, with minute, sparse, piligerous punctures. Mandibles and antennae subopaque, the former sparsely and coarsely punctate.

Hairs yellow, short, bristly, suberect, longer on the clypeus and gaster. There is a long bristle at each humeral angle, one on each side of the mesonotum near the base of the epinotum and one on each side of the petiolar and postpetiolar nodes.

Brownish yellow; legs and antennae a little paler; mandibles and clypeus a little darker.

Described from numerous specimens taken from a single colony at Malela by Lang, Chapin, and Bequaert in a mound-shaped termitarium of Acanthotertnes militaris (Hagen). The latter contained beautiful fungus-gardens, which are shown in Plate XVI. The cavities inhabited by the Paedalgus colony were in the walls of the fungus chambers at a spot corresponding to the upper right hand corner of the figure.

P. termitolestes is certainly very close to Santschii infimus but differs in its somewhat larger size ( infimus measures only 0.8 mm.) and in having the head longer than broad, with shorter and stouter scapes, a somewhat longer thorax, less transverse petiolar and postpetiolar nodes, and in having the promesonotum opaque.

The specimens of the new species were accompanied by great numbers of worker larvae and pupae and nearly adult female larvae. They are white, nearly spherical, with short neck, small head, and very feebly developed mouth-parts, indicating that they are fed by the tiny workers with regurgitated liquid food. They are not "glabres," as Santschi describes the larvae of P. infimus , but covered uniformly with short, stiff, sparse hairs, each of which has two recurved branches (Fig. 43a and b). Even in alcohol, the larvae cling compactly together in masses by means of these hooks. When stained and cleared, the larvae are seen to possess unusually voluminous salivary glands. The youngest individuals, scarcely 0.2 mm. long, have the receptacle full of clear secretion (Fig. 43a). In older larvae (Fig. 43b), the secretion after dehydration forms great masses in the receptacles and lumen of the glands. As these organs are not used in spinning a cocoon, it is very probable that the secretion, like the exudate of Viticicola , and Pachysima larvae described above, is elaborated and used as a food for the workers (trophallaxis).

The observations of Lang, Chapin, and Bequaert show that the African species of Paedalgus have the same habits as the Ceylonese P. escherichi and as the species of Carebara . Since, however, the majority of African termites cultivate fungus-gardens, the interesting question as to whether the minute workers of Paedalgus feed on the termites, on the fungus mycelium, or on both can be answered only by future observations on artificial compound nests of the ants and their hosts.