L'arme frontale des soldats de termites. I. Rhinotermitidae

The frontal gland of termites is a single tegumentary gland. In the soldiers of Rhinotermitidae it corresponds to an invagination which opens at the front of the head by the frontal pore or fontanelle. This gland is well developed and generally extends into a large part of the abdomen. Using scanning electron microscopy we state a more precise picture of the frontal weapon, which consists of the frontal gland, the pore and its associated cephalic structures (frons, clypeus and labrum) involved in the defensive system of the insect. Many isolated glandular pits occur on the labrum or around the frontal pore, forming in the latter case a punctured area. This morphological data is interpreted, as far as possible, from a functional point of view. These observations also permit us to extend the study of the phylogenetic relations within the Rhinotermitidae. The subfamilies are readily distinguishable, each having retained a group of primitive characters and developed a set of evolved characters. The Rhinotermitinae, with the exception of one genus, Prorhinotermes, possess a characteristic labral «daubing brush». They form a coherent group throughout which the gradual specialization of the frontal weapon can be traced. The genus Prorhinotermes is therefore removed from the Rhinotermitinae the form a monotypic subfamily, Prorhinotermitinae (Subfam. nov.) characterised in the soldier caste by its oval head, toothless mandibles, small fontanelle, and lack of a labral brush. © 1975 Masson & Cie.SCOPUS: ar.j