"In a favorable season, when the weather is warm and food plentiful, a nest may contain many thousands of cells full of wasps in various stages of development, and, as each cell is occupied two or three times in the course of a summer, those authorities who put the number of the members of the community as high as thirty thousand are probably not far wrong.
"At the approach of autumn the society begins to break up; the males fertilize the females while flying high in the air; they then die, often within a few hours. The workers leave the nest, carrying with them any grubs that remain in the cells, and both soon perish. The nest is entirely deserted. The females which have been fertilized creep into crevices under stones or trees or hide among moss, and hibernate until the warmth of the following spring induces them to leave their hiding places and set about founding a new community."
Where hornets or wasps occur in very large numbers they frequently, at certain seasons, do considerable damage to fruit and forest trees by gnawing off the bark to build their paper nests. They destroy the fruit they attack, living as they do upon the juices extracted from it. But, on the other hand, these insects are very useful in that they likewise feed on flies and other insects, and so very materially diminish the numbers of these pests. Some wasps live in part upon honey, which they collect from the most open-petaled flowers, and thus to a very moderate extent they may be regarded in the light of flower fertilizers. Kirkland says, in the first volume of the American Naturalist, that "the paper hornet (Vespa maculata) often enters my nucleus hives, when I am rearing Italian queen bees, and captures the young queen in the midst of her little colony, usually just after she has commenced her first laying. I have seen this depredator enter the small hive, drag out the queen, and fly away with her to the woods" (page 52). Some of the species of the genus Polistes store up honey which is poisonous, from the fact that it has been collected from poisonous flowers. They are found in South America, where also species of the genus Chartergus occur—wasps that make a very remarkable and tough nest, with funnel-shaped combs inside, arranged one inside of another, nest fashion, but not in contact except at their points of suspension. At the apices of these cones occur the apertures of entrance for the inmates to pass up among the conical tiers. Icaria, a genus represented in Australia, the East Indies, Africa, and Madagascar, contains some very remarkable species. Some of them have the power of contracting the hinder segments of the abdomen so far within the body that at first sight they appear to have been broken off. Many of these species are very small and brilliantly colored, and often build curiously shaped little paper nests.
