With these facts before me, I believe that natural selection, by acting on the fertile ants or parents, could form a species which should regularly produce neuters, all of large size with one form of jaw, or all of small size with widely different jaws; or lastly, and this is the greatest difficulty, one set of workers of one size and structure, and simultaneously another set of workers of a different size and structure; a graduated series having first been formed, as in the case of the driver ant, and then the extreme forms having been produced in greater and greater numbers, through the survival of the parents which generated them, until none with an intermediate structure were produced.
Egitateok aurrean ditudala, uste dut hautespen naturalak, inurri ugalkor edo gurasoengan ihardunez, normalean tamainu handiko eta forma bereko barailadun neutroak sortuko zituen espezie bat forma zezakeela, edo guztiak tamainu txikikoak eta baraila oso diferentedunak, edo, azkenez, eta hauxe da zailtasunik handiena, tamainu eta egitura bateko langile mota bat eta, aldi berean, tamainu eta egitura diferenteko beste langile mota bat; lehenbizi serie mailakatu bat formatuko zen, inurri ehiztariaren kasuan bezala, eta orduan ertzeko forma gero eta gehiago formatuko ziren, berauek sortu zituzten gurasoen biziraupenaren bidez, harik eta bitarteko egituradun inurririk sortu ez zen arte.