The Nest of an Anomalous Colonyof the Arboreal Ant Cephalotes Atratus

One ,of the distinctive elements of the neotropical ant fauna is the.heavily armored and spinose genus.Cepha.lotes of forested areas.The workers have powerful, short and convex mandibles that enable them to.gnaw out cavities in the trees for nests.Kempf (1951) lists the species atratus (L.) from Honduras t.o Brazil and northern Argentina and summarizes the known biological records.He has also synonymized quadridens De Geer with atratus.As thus known, the worker is characterized as 8 to 14 mm and black in color and the female about 20 mm and black.The male length is up t,o 14 mm and with head, thorax and penduncle black, gaster and appendages testaceous to dark ferruginous.Other characters of the castes are fully described by him.Under the name of Cephalotes atratus quadridens the present colony has been alluded to briefly (Weber, 1938, 1947; Wheeler, 1937; Whiting, 1938) and a figure ,of one of the anomal.ousw, orkers has appeared (Wheeler, 1936).No account of its biology or nest has hitherto, been pub- lished.Observations .on the col,ony were initiated on December 11, 1934 and terminated on October 4, 1935, during tenure of a National Research Fellowship in Biology.It is one of two known ant colonies that contained un- precedented numbers of anomalous individuals.Both were discovered and .observedby the writer in Trinidad, B. W. I.and the other (Acromyrmex octospinosus Reich) was the subject ,of the book by Dr. Wheeler ( 1937).The Acromyrmex anomalies were considered by him to be.mosaics or gynandr.omorphsbut were later (Whiting, 1938) tentatively ,characterized as intersexes and intercastes.Dr.Whiting suggested that the Cep.halotes anomalies, called 6O