Looked at in this light, the present pages and those of the preceding work may be regarded as so many drawers in our _Cabinet of Habits_, and though, as we open drawer after drawer, many gaps and blank spaces remind us how much remains to be done in order to complete the collection, yet the interest and suggestiveness of the specimen-facts already secured, should encourage and direct us onwards. There have not been wanting instances in which my readers have associated themselves with me in the way indicated, and it is with pleasure, when reviewing the entire work, that I recall how many of its most interesting features are due to the researches and assistance of friends,[109] and commemorate at once their discoveries and unfailing kindness. I had certainly expected that before this time some new species of harvesting ants would have been discovered, either on the Riviera, where attention has been especially called to the subject, or in other parts of Europe, where dissimilar conditions might have been expected to be associated with a different fauna; but this has hitherto not been the case. [Footnote 109: To all who have rendered me this valuable help I tender my cordial thanks. I am under very special obligations to Mr. Pickard-Cambridge, for descriptions of spiders, and to Mr. F. Smith for the names of the Ants; assistance which I should have found it almost impossible to dispense with or to replace.] One might naturally suppose that if harvesting ants were discovered in localities very widely distant from each other, they would prove to belong to different species, but thus far, both in Europe and Northern Africa, it is the same two well-known species of _Atta barbara_ and _A. structor_ that constantly reappear. For instance, I have recently learned that harvesting ants are found at Cadenabbia on the lake of Como, and at Montpellier in Southern France; but on examination, the ants from the former place are clearly seen to belong to the species _structor_, and those from Montpellier to the two species _structor_ and _barbara_.