I shall relate two more instances of the use of a reasoning faculty in these ants. I once saw a wide column trying to pass along a crumbling, nearly perpendicular, slope. They would have got very slowly over it, and many of them would have fallen, but a number having secured their hold, and reaching to each other, remained stationary, and over them the main column passed. Another time they were crossing a water-course along a small branch, not thicker than a goose-quill. They widened this natural bridge to three times its width by a number of ants clinging to it and to each other on each side, over which the column passed three or four deep. Except for this expedient they would have had to pass over in single file, and treble the time would have been consumed. Can it not be contended that such insects are able to determine by reasoning powers which is the best way of doing a thing, and that their actions are guided by thought and reflection? This view is much strengthened by the fact that the cerebral ganglia in ants are more developed than in any other insect, and that in all the Hymenoptera, at the head of which they stand, "they are many times larger than in the less intelligent orders, such as beetles."* (* Darwin, "Descent of Man" volume 1 page 145.) The Hymenoptera standing at the head of the Articulata, and the Mammalia at the head of the Vertebrata, it is curious to mark how, in geological history, the appearance and development of these two orders (culminating, one in the Ants; the other in the Primates) run parallel. The Hymenoptera and the Mammalia both make their first appearance early in the secondary period, and it is not until the commencement of the tertiary epoch that ants and monkeys appear upon the scene. There the parallel ends. No one species of ant has attained any great superiority above all its fellows, whilst man is very far in advance of all the other Primates.