[Illustration: OSWEGO TEA OR BEE BALM. (_Monarda didyma._) FROM "NATURE'S GARDEN." COPYRIGHT 1900, BY DOUBLEDAY, PAGE & COMPANY.] FLOWERS AND THEIR UNBIDDEN GUESTS. In the September number we considered flowers and their invited guests, that is the insects useful in carrying pollen. The very things which attract useful insects to flowers are attractive also to useless insects. For example, nectar in a flower seems just as desirable to an ant as to a butterfly, but the ant is a creeping insect and would be likely to lose the pollen in passing from one plant to another. If useless insects found free access to flowers and carried off their food supplies, the useful insects would soon stop visiting them. It is of great advantage to flowers, therefore, to have some means of warding off the creeping insects. It must not be understood that all plants are equally successful in this matter, or that any plant is always successful, but there are certain things which seem to hinder or discourage the approach of creeping insects to flowers. Perhaps ants may be taken as the best illustration of the insects whose visits are discouraged by flowers. They are very much attracted to the food supplies in the flower, especially the nectar, and are among the most intelligent of insects, often overcoming the most serious obstacles. They will be considered in this paper, therefore, as the insects which are seeking the nectar and pollen of flowers without invitation. A charming little book upon this subject has been written by Kerner, and translated into English, under the title which appears at the head of this paper. It is in this book that the chief obstacles to such unwelcome guests as ants are clearly stated. Hairs.--One of the most common obstacles to ants is a barrier of hair. For some reason, ants dislike to cross such a barrier. Travellers in tropical countries, where ants abound, tell us that a hair rope laid around a tent is a very effective barrier against the invasion of armies of ants. Hair is very commonly found upon plants, and it may be noticed that it is apt to increase in amount and prominence towards or within the flower cluster. Sometimes the flowers themselves are hairy outside, and in the case of the trailing arbutus, whose flowers close to the ground are in special danger from creeping insects, the flowers are filled with a fluffy mass of hairs. In our illustrations, the wild columbine, the Oswego tea, the sunflower, and the ox-eye daisy are all hairy plants, and difficult for ants to climb. In the September number are illustrations of the mallow, the lady's slipper, and the New England aster, all of which are hairy and discouraging to ants.