Orectognathus

Smith, F., 1858, Catalogue of the hymenopterous insects in the collection of the British Museum. Part VI. Formicidae., London: British Museum : 141

Genus 6. HEPTACONDYLUS, Smith.

Head suborbiculate, wider than the thorax; eyes lateral and ovate; the stemmata placed in a triangle on the vertex; antennae geniculated, filiform, the scape nearly as long as the flagellum, placed forwards on the head at the base of the clypeus; the flagellum6-jointed, the joints clavate, except the apical one, which is cylindrical; the labial palpi 3-jointed, the maxillary palpi 3-jointed. Thorax ovate, gibbous; the scutellum very prominent; the metathorax armed with two acute spines (in the female), compressed and strangulated (in the workers); the superior wings with one marginal and one complete submarginal cell, the submarginal cell receiving the recurrent nervure; the superior angle of the discoidal cell touching the costal nervure. Abdomen ovate; the peduncle composed of two nodes.

This genus presents a remarkable deviation from the general rule, as exemplified in the aculeate Hymenoptera; thus the normal number of joints in the antennae of the females being 12, and 13 in the males, as a general rule, serves to discriminate the sexes: the workers also have usually 12-jointed antennae, but in the present genus both the female and worker have only 7 joints. The genus Orectognathus has only 5 joints in the antennae, but only workers are known. In Heptacondylus , however, the female has the same reduced number of joints as the worker, and this must be considered the perfect condition of the species.