During the winter and spring I kept two colonies of _barbara_ captive in the house, placed in separate glass jars, each of which might perhaps hold half a gallon. The former of these colonies was taken on December 18; but neither the queen ant nor larvæ were found, though there probably were larvæ in some unexplored part of the nest, and the ants were always restless and miserable, unceasingly trying to escape, and dying in large numbers. On February 12 I found that all these ants, though abundantly supplied with seeds and all other kinds of food, were dead. Two other colonies of ants, however, which had been taken in a torpid state in the masses of earth which formed part of the original nest, were alive and well, though still torpid. The second captive colony, taken on December 28, with the wingless queen ant and quantities of larvæ, formed a strong contrast with the previous one. Here the ants at once set to work upon the construction of galleries and safety places for the larvæ below the even surface of garden mould on which I had placed them within the jar; for in this case I did not attempt to preserve any portion of their own nest. This was done at 3.30 P.M., and by 9 that evening I found the ants most busily at work, having in less than six hours excavated eight deep orifices leading to galleries below, and surrounded these orifices by crater-like heaps, made of the earth pellets which they had thrown out. I have observed somewhat similar structures raised by _barbara_ after the nests have been closed on account of rain, and _structor_ frequently raises still more elaborate and distinct craters, such as those represented at Fig. B, Plate II., p. 22 (reduced one-half). On the following morning the openings were ten in number, and the greatly increased heaps of excavated earth showed that they must probably have been at work all night. The amount of work done in this short time was truly surprising, for it must be remembered that, eighteen hours before, the earth presented a perfectly level surface, and the larvæ and ants, now housed below, found themselves prisoners in a strange place, bounded by glass walls, and with no exit possible.