In the works of Huber and others, further marvels of hive-life, some well-authenticated, others more or less doubtful, are duly set forth. But enough has here been said to show that a social community of bees presents problems of animal behaviour which are sufficiently difficult of explanation. How far is the behaviour instinctive? How far is it due to experience individually acquired? Are we constrained to admit a rational factor? If so, is it, like human reason, the result of generalization from experience of the relationships of phenomena? Or are there features of insect psychology which differ from any of which we have firsthand knowledge? These questions are more easily put than answered. As in the case of bird-migration, so too in that of the social life of bees, there is much that honesty forces us to confess our inability satisfactorily to explain. So, too, is it in the social life of ants. Among these insects the males and perfect females bear wings, though these appendages may be subsequently shed. In some kinds, however, there are also wingless males or females capable of exercising the reproductive function. The workers are wingless, and are often of two or three kinds, differing in form and appearance, and in some cases playing different parts in the social economy. There is also, in some cases, a separate class of large-headed soldier ants; so that differentiation of structure among the sterile females is carried further in ants than in bees. Their nests generally consist of an elaborate system of chambers and passages, either built with pine-needles, as in our common wood ant, or hollowed out in the earth or in wood, or sometimes built with a paper-like material, or formed of rolled leaves. It is said that a common ant in Eastern Asia (_Œcophylla smaragdina_) “forms shelters on the leaves of trees, by curling the edges of leaves and joining them together.... The perfect ant has no material with which to fasten together the edges it curls; its larva, however, possesses glands that secrete a supply of material for it to form a cocoon with, and the ants utilize the larvæ to effect their purpose.”[91] This has recently been confirmed by Mr. E. G. Green, Government entomologist, at the Botanic Gardens at Peradeniya, Ceylon. “He has seen ants actually holding larvæ in their mouths and utilizing them as spinning machines. To find out what would be done, some leaves were purposely separated by Mr. Green. The edges of the leaves were quickly drawn together by the ants, and, about an hour later, small white grubs were seen being passed backwards and forwards across the gaps made in the walls of the shelter. A continuous thread of silk proceeded from the mouth of the larva, and was used to repair the damage.”[92] This is a remarkable act of apparently intelligent behaviour. But when we remember how much of the time of ants is occupied in carrying about their larvæ, it is hardly an act of which it can be affirmed that it could not arise as