The attention of Ants to public hygiene is more than equalled by their attention to personal hygiene. Without going into the question of their athletic exercises, which have attracted considerable attention, it is sufficient to quote one observer as to their habits of cleanliness. McCook remarks:--"The Agricultural Ants--and the remark applies to all other Ants of which I have knowledge--is one of the neatest of creatures in her personal habits. I think I have never seen one of my imprisoned harvesters, either _Barbatus_ or _Crudelis_, in an untidy condition. They issue from their burrows, after the most active digging, even when the earth is damp, without being perceptibly soiled. Such minute particles of dust as cling to the body are carefully removed. Indeed, the whole body is frequently and thoroughly cleansed, a duty which is habitually, I might almost venture to say invariably, attended to after eating and after sleep. In this process the Ants assist one another; and it is an exceedingly interesting sight which is presented to the observer when this general 'washing up' is in progress."[112] [112] H. C. McCook, _Agricultural Ants of Texas_, 1879, chapter on "Toilet, Sleeping, and Funeral Habits," p. 125. _Prudence of Bees._--Certain species exhibit very great prudence, especially the _Melipona geniculata_, which lives in a wild state in South America. They place their combs in the hollow of a tree or the cleft of a rock; they fill up all the crevices and only leave a round hole for entry. And even this they are accustomed to close every evening by a small partition, which they remove in the morning. This door is shut with various materials, such as resin or even clay, which the bees bring on their legs as those of our own country bring pollen. All these facts were observed with great exactness in a swarm given in 1874 by M. Drory (who during a long period of years studied every Brazilian species of _Melipona_ at Bordeaux) to the Jardin d'Acclimatation. It was even seen that the door might be put up under certain circumstances in open day, as for example, when a storm or sudden cold delays the appearance of the workers. If one of them happened to be late it had to perforate the partition, and the hole was then stopped up again. [Illustration: FIG. 42.]