aliens who are excludable on mental, physical, moral or economic grounds. These include the insane, the idiot and the feebleminded; those who have loathsome or dangerous contagious diseases; criminals; prostitutes; persons physically incapacitated from earning a living, illiterates, etc. In fact the enumeration of the undesirable classes is so complete that, if the law had been and were always rigidly enforced, our immigration "problem" would. give us far less trouble than it does. Our law bars criminals, but our court and institution records show a large excess of foreignborn. Our law bars the insane, but our insane hospitals, especially in the northeastern States, are filled with aliens. Our law bars those suffering from loathsome and dangerous contagious diseases, and those suffering from physical disability that may affect ability to earn a living, but political "pull" often suffices to admit over the doctor's certificate, against the express provision for exclusion. Our law debars paupers; yet an insignificant number of aliens is debarred on these grounds, although the majority of those now arriving come without money, and are not productive laborers.

In a recent paper on the deportation system of several States, Dr. H. H. Laughlin, of the Eugenics Record Office, Cold Spring Harbor, N. Y., brought together some startling facts.

A recent survey shows that in 1916 the several states expended on an average of 17.3 per cent. of their total governmental expenditures in maintaining custodial and charitable institutions. This percentage varied from 5.4 in Alabama to 30.5 in Massachusetts. A survey of 460 state institutions for the several types of the socially inadequate, with a total of 210,835 inmates, recently (1922) completed by the Committee on Immigration and Naturalization of the House of Representatives, found 21.14 per cent. of these fifth of a million inmates to be of foreign birth and 44.09 per cent. to be of foreign stock-that is, of foreign birth or who have at least one parent foreign born. Thus if, on the average, it costs the same in the institutions to maintain native-born and foreign-born inmates, then currently the several states are expending approximately 7.62 per cent. of their total revenues in caring for degenerate and dependent human foreign stock. This is the logical outgrowth of the asylum idea which has pervaded the American immigration policy.

The proper enforcement of our general immigration law involves not only a very careful and deliberate scrutiny of all arriving aliens, but also a systematic and thorough round-up of all aliens already in this country who are deportable because they have become public charges, or who have been found to belong to certain other specified classes of undesirables which are by law subject to deportation. Never yet since the law of 1917 has been on our statute books has it been strictly enforced. It is to the credit of the present administration that a distinct improvement in

this respect was made during the past year. And it should be remembered that strict enforcement leads to a certain extent to selfenforcement, for the more aliens are debarred as undesirable, the fewer such attempt to get in.

THE PERCENTAGE LIMITATION MUST BE MADE PERMANENT

The present 3 per cent. law is not perfect, but it has on the whole worked successfully, and has fully justified its enactment. It is reasonably generous in permitting the reuniting of families; in allowing unrestricted entry to tourists and other excepted classes, and it has kept our ports open to a fairly considerable inflow of newcomers, for it should be remembered that it permits an annual immigration of over 350,000. It has undoubtedly worked hardships in some cases, but most of the newspaper stories of such hardships have either been intentionally exaggerated, or have been untrue. Public sympathy is easily aroused by a single instance of real or fictitious hardship. The far more vital problem of how the present character of immigration is to affect the American race of the future is more remote, and attracts less attention. The administration of the law is fortunately in the hands of officials who are enforcing it with justice and humanity.

There is one point in connection with the 3 per cent. law which is often lost sight of. For a good many years before the war, aliens from southern and eastern Europe largely outnumbered those from northern and western Europe. Under the new law these numbers are nearly equalized, so that if all nationalities fill their allotted quotas, the so-called "newer" immigration can not contribute more than about one half of our annual inflow. This fact is biologically of great significance. In the fiscal year ending June 30, 1922, deducting emigrants from immigrants, we gained in Nordic stock, and lost in the natives of southern and eastern Europe.

Those who attribute solely to the present percentage restriction the need of labor in certain industries are either wholly ignorant of the facts, or are intentionally trying to mislead the public in the effort to break down all restrictions and to flood the country with cheap labor. In this connection it should be realized that (1) there has been a very considerable emigration of alien labor during the recent period of business depression and unemployment; (2) if all countries filled up their quotas, which they have not been doing during the past year, there would be an annual inflow of over 350,000; (3) the countries of northern Europe have fallen much farther below the quotas than those of southern and eastern Europe, most of the latter having exhausted their quotas, thus showing that the intelligent and skilled labor of northern Europe

All the primitive ants are decidedly carnivorous, that is predatory hunters of other insects. That this must have been the character of the whole family during a very long period of its history is indicated by the retention of the insectivorous habit, in a more or less mitigated form, even in many of the higher ants. Always striving to rear as many young as possible, always hungry and exploring, the ants early adapted themselves to every part of their environment. They came, in fact, to acquire two environments, each peopled by a sufficient number of insects, arachnids, myriopods, etc., to furnish a precarious food-supply. Most of the ants learned to forage on the exposed surface of the soil and vegetation and became what we call epigæic, or surface forms, while a smaller number took to hunting their prey beneath the surface of the soil and thus became hypogæic, or subterranean. Many of the latter are very primitive but their number has been repeatedly recruited from higher genera, which by carrying on all their activities within the soil have found a refuge and surcease from a too strenuous competition with the epigaic species. We have here some very interesting cases of convergence, or parallel development, since the underground habit has caused the workers, which rarely or never leave their burrows, to lose their deep pigmentation and become yellow or light brown and to become nearly or quite blind. As will be evident in the course of my discussion, the tendency towards vegetarianism is apparent among both the epigæic and hypogæic forms.

The ants belonging to the oldest and most primitive subfamilies, the Ponerinæ, Doryline and Cerepachyinæ and also to many of the lower genera of Myrmicinæ, feed exclusively on insects and therefore represent the hunting stage of human society. Owing to the difficulty of securing large quantities of the kind of food to which they are addicted, many of the species form small, depauperate colonies, consisting of a limited number of monomorphic workers. Many of these species lead a timid, subterranean life. In the size of their colonies, which may comprise hundreds of thousands of individuals, the Doryline alone constitute a striking exception, but one which proves the rule. These insects, known as driver, army or legionary ants and very largely confined to Equatorial Africa and tropical America, are strictly carnivorous, but being nomadic and therefore foraging over an extensive territory, are able to obtain the amount of insect food necessary to the growth and maintenance of a huge and polymorphic population. They are the famous ants whose intrepid armies often overrun houses in the tropics, clear out all the vermine and compel the human inhabitants to leave the premises for a time. In Africa they have been known to kill even large domestic animals when they were tethered or penned up and thus prevented from escaping.

The pastoral stage is represented by a great number of Myrmicine and especially of Formicine and Dolichoderine ants which live very largely on "honey-dew." This sweet liquid, concerning the origin of which there was much speculation among the ancients, is now known to be the sap of plants and to become accessible to the ants in two ways. First, it may be excreted by the plants from small glands or nectaries ("extrafloral nectaries") situated on their leaves or stems, where it is eagerly sought and imbibed by the ants. Second, a much more abundant supply is made accessible by a great group of insects, the Phytophthora, comprising the plant-lice, scale-insects, mealy-bugs, leaf-hoppers, psyllids, etc., which live gregariously on the surfaces of plants. These Phytophthora pierce the integument of the plants with their slender, pointed mouth-parts and imbibe their juices which consist of water containing in solution cane sugar, invert sugar, dextrin and a small amount of albuminous substance. In the alimentary canal of the insects much of the cane sugar is split up to form invert sugar and a relatively small amount of all the substances is assimilated, so that the excrement is not only abundant but contains more invert and less cane sugar. This excrement or honey-dew either falls upon the leaves and is licked up by the ants or is imbibed by them directly while it is leaving the bodies of the Phytophthora. Many species of ants have learned how to induce the Phytophthora to void the honey-dew by stroking them with the antennæ, protect and care for them and even to keep them in specially constructed shelters or barns. Some ants have acquired such vested interests in certain plant-lice that they actually collect their eggs in the fall, keep them in the nests over winter and in the spring distribute the hatching young over the surface of the plants. Linnæus was therefore justified in calling the plant-lice the dairycattle of the ants ("ha formicarum vacca"). This dairy business is, in fact, carried on in all parts of the world on such a scale and with so many species of Phytophthora that it constitutes one of the most harmful of the multifarious activities of ants. Their irrepressible habit of protecting and distributing plant-lice, scaleinsects, etc., is a source of considerable damage to many of our cultivated plants and especially to our fruit-trees, field and garden crops. Ants mostly attend Phytophthora on the leaves and shoots of plants, but quite a number of species are hypogaic and devote themselves to pasturing their cattle on the roots. Thus our common garden ant (Lasius americanus) distributes plant-lice over the roots of Indian corn.

The habit of keeping Phytophthora was probably developed independently in many different genera, and it is easy to see how the habit of feeding by mutual regurgitation among the ants themselves might have led to the behavior I have been describing. Cer

Vol. XV. 34.

tainly the genera that have developed trophallaxis among the adult members of their colonies are the very ones which most assiduously attend the Phytophthora. And it is equally certain that the latter habit is very ancient, because it was already established among the ants of the Baltic Amber during Lower Oligocene times and that, as we have seen, was many million years ago.

The dairying habit has led to an interesting specialization in certain species known as "honey ants," which inhabit desert regions or those with long, dry summers. These ants have found it very advantageous to store the honey dew collected during periods of active plant growth, and as they are unable to make cells like those of wasps and bees, have hit upon the ingenious device of using the crops of certain workers or soldiers for the purpose. In all ants, as we have seen, the crop is a capacious sac, but in the typical honey ants it becomes capable of such extraordinary distention that the abdomen of the individuals that assume the rôle of animated demijohns or carboys, becomes enormously enlarged and perfectly spherical. Such "repletes" (Fig. 66) are quite unable to walk and therefore suspend themselves by their claws from the ceilings of the nest chambers. When hungry the ordinary workers stroke their heads and receive by regurgitation droplets of the honey dew with which they were filled during seasons of plenty. The condition here described, or one of less gastric distention, has been observed in desert or xerothermal ants in very widely separated regions and belonging to some nine different genera of Myrmicinæ, Formicinæ and Dolichoderinæ (Myrmecocystus and Prenolepis in the United States and Northern Mexico, Melophorus, Camponotus, Leptomyrmex and Oligomyrmex in Australia, Plagio

a, lateral