Wheeler, W. M., 1922:
Three large workers from Faradje, Niangara, and Medje, taken from the stomachs of toads (Bwfo regularis and B. superciliaris) and a frog (Rana occipitalis); also a large series of workers from Farad je (Lang and Chapin).
This form closely resembles subspecies burmeisteri varietymolestus (Gerstaecker) in having the inferoposterior angles of the petiole prolonged outward as distinct tubercles, but is readily distinguished by having the head of the larger workers (7 to 12.5 mm.) opaque instead of shining and that of the smaller workers elongate.
An interesting account of the habits of rubellus and sjoestedti has been published by Sjostedt.1