As far as the manner of collecting and storing the seed is concerned, all that has been said of _Atta barbara_ applies with equal truth to _A. structor_. _A. structor_ is, however, less frequently seen above ground from December to March than _barbara_, and is more frequently found in or near the streets and gardens of a town. The fourth species, on the other hand, the little _Pheidole megacephala_, differs in several particulars. This ant appears to shun the daylight, and to be most active at night, when, in the warm weather at the end of April, it may frequently be seen carrying large quantities of seeds into its nest. I have rarely observed it at work in the daylight, so that my knowledge of its habits is but small. Nor have I succeeded in discovering its subterranean granaries, though I have opened several nests. Still, I believe that it is a true harvesting ant, and not merely a casual collector of seeds. Of the habits of _Pheidole pallidula_, a very closely allied and similar species, but one less frequently met with, I cannot speak with certainty, though it is quite possible that it also may be a true harvester, in which case it would add a fifth species to this class. Both _Pheidole megacephala_ and _Ph. pallidula_ appear to remain inactive, or nearly so, during the months from November to April, and it is probable that they are only to be seen in full activity during the summer when I am not there to watch them. There can be little doubt that any naturalist who will take the pains to note the habits of ants on the shores of the Mediterranean through June, July, August, and September, might collect a most interesting series of observations on harvesting and other species, and add to, and perhaps modify, those which my limited opportunities have enabled me to make. There are three other ants[33]--namely, _Formica emarginata_, _F. fusca_, and _Myrmica cæspitum_, which may also occasionally be found carrying a few seeds, but this is the rare exception, as far as my experience goes, these species living on honey dew, sweet secretions, and animal matter, like the great majority of ants all over the world. I have never found seeds in the nests of any ants except those of _Atta barbara_ and _A. structor_, though I have carefully searched for them in most of the nests of the sixteen species of ants whose habits I have watched. [Footnote 33: For some details of the habits of the sixteen species of ants observed on the Riviera, see Appendix A.]