E V I Mmsemnn of Coinnparative Zoology Cambridge, Mass. August 29, 1952 Number 6 CONTRIBUTIONS TOWARD A RECLASSIFICATION OF THE FORMICIDAE I. Tribe Platythyreini (Hymenoptera) By William L. Brown, Jr. Museum of Comparative Zoology Harvard University The tribe Platythyreini has included the sole genus Platythyrea Roger as treated by former authors. My own investigations show that three additional genera {Proholomyrmex, Escherichia and Eubothro-ponera) must be included. Proholomyrmex Mayr and Escherichia Forel have heretofore been placed among the Proceratiini because of their depigmented condition, atrophied eyes (workers), and especially their vertical, fused and approximated frontal carinae and the closeness of the antennal insertions to the median line and to one another, accompanied by fusion of frontal carinae with the greatly crowded clypeus. Also, these two genera have, according to the describers of the included species, only one tibial spur to each of the two posterior pairs of tibiae. I believe that all of the characters just mentioned are correlated with adaptation of the insects to hypogaeic or other crypto-biotic conditions of life; they appear in widely separated genera of ants and other hymenopters, such as Proceratium, Discothyrea and others in the Formicidae, Psilohethylus, etc. in the Bethylidae, and so on, as rather consistent combinations. The similar modifications of doryline and some other ants may be partly due to hypogaeic or subhypogaeic adaptation, but it would seem that the legionary habit may somehow be more important in accounting for this particular structural modi-fication. For our present purposes, it will be sufficient merely to recognize two facts: (1) the characters combining to produce the "proceratiine
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