IT is a matter of common knowledge that the ^ damage occasioned by locust invasions is frequently extremely serious. Thus, in the year 1874, the destruction brought about by these insects in the Rocky Mountains amounted to approximately forty million dollars. In 1908 an estimated damage of one million sterling was caused by locusts to crops in the Transvaal, while the cotton crop in Egypt has often suffered severely. The intensity of an attack, and some idea of the damage done, may be gauged from the number of locusts often found within a comparatively small area. For example, in Southern France in 1920, between twelve and thirty million locusts were destroyed daily, while twenty tons of eggs were collected in a single month in the Argentine in March 1915. Since the year 1914 the countries affected by locusts include the greater part of Africa, certain parts of Spain, France, Italy, Asia Minor, Turkestan, etc. The regions more especially affected lie between 20° and 40° latitude north and 15° and 45° latitude south, the equator being comparatively immune. In order to deal with these outbreaks some international organisation appears necessary, and it is to be hoped that the League of Nations will lend its authority to assist in arriving at a concerted plan of action. The need for international action is obvious when it is remembered that locust swarms can travel 18 to 300 miles in a single day, thus easily migrating from one country into another.