Relation ofVualfiy and Qttntit* of Food to the Production of the Sexless Workers.— As is obvious, the' workers rarely lay eggs, the worker caste is not inherited either directly or collaterally from the parents. The view now suggested and supported by a con siderable body of facts is that the larva on hatching are at first all alike and that those which become workers are fed with different as well as less food than those which develop into sexual individuals. We know that the differendes between the queen and the 'worker bees are due to differences in the nature of the food. The worker white ants. have been found by Grassi to be the , result of . having different food and leks -of it than the males or females. Wasnann believes that the large workers of Polyergus rufescens (tergatoid femalet*) are produced by the slave ants (For mica 'urea), living in the colony, through ex cessive care and feeding of certain larva—that is, that the fusca workers or slaves attempt to change worker larva of Polyergus into queens, but succeed only in producing the wingless Emery also holds that the sexual polymorphism of the ant colony is the result of the development of 'an instinct in the workers to feed the larvae in different ways and thus the characters in which the worker differs from the corresponding sexual forms are not con genital but acquired.
As has been said -the female ant, on found ing a new colony, herself lives, and nourishes the freshly-hatched larvae with food from her stomach, ultimately from the fat-body. Hence these !arm of the first brood are poorly fed and become small or dwarf workers (micro-ergates), These workers leave the nest and bring in food to their half-starved parent. Thus fed she be comes more prolific, lays another batch of eggs and the 'arm become larger and finally change into larger-sized workers. The colony thus be comes more populous and, as Wheeler states, the workers of successive broods grow larger until they attain the full stature of the species. Then and not till then do the workers bring up the males and queens, which are carefully herd ed, fed and groomed by the workers until ready for the marriage flight. In some species of ants the males and virgin queens do not appear till the second cir third year after the colony is founded. In a few American species of the huge cosmopolitan genus Pheidole, Wheeler and others find that the large-headed and small headed or dwarf workers are connected by a perfect series of intermediate forms and this is due to the varying quantity of food. After an unfavorable season (autumn and winter) of drought and cold the number of Pheidole sol diers was unusually small. Thus Grassi's view as to the origin of the polymorphic forms in the termites being dependent on the quality and quantity is borne out by recent observations on ants.
Polymorphism and Variability of Ant No solitary ants are known to exist, in all besides the males and females there are workers, and this is the direct result of their social mode of life. In our common species there is only one kind of worker, those in which the head is of uniform size, no big-headed ones or soldiers. But in ants collectively, though not in any one genus, there • may be eight sets of individuals — that is, ordinary males and males, ordinary females and erga toid fertile females, and exceptionally (Formica tufa), a set intermediate between the female and the worker; there are also soldiers, worker majors and one or more kinds of worker minors. The adult, sexually capable, though wingless forms, ire called by Ford "lergatoids* from their resemblance to workers ('Rigyarti a worker), this term is applied to both sexes. The worker females differ from the normal winged female in the lack of a receptaculum setintiss. The greatest number of castes in any one genus is five, occurring in 'Eciton, Crypto cerus.
Wheeler shows that polymorphism and va riability depends on the amount and nature of the food and the increase in the population of the colony, and on the care and protection af forded to the reproductive individuals of the colony. There is, on the other hand, little va riation in colonies which are poorly fed and therefore unable to increase rapidly in number, Primitive Two primitive sub families of ants, the Dorylince and Poneriner, appear to have been evolved from a still more primitive and ancestral group, the Cerapoehynce, which Wheeler with good reason claims to be tithe most archaic and generalized of existing Formicide.D This group, species of which occur in Africa, southeastern Asia, Australia and tht southwestern United States (Texas) is repre tented in this country by Cerapachys, which mines the ground for a few inches under stones.
The colony appears to be unusually small, the queen is wingless and the workers quite blind, and its life appears to be wholly subterranean, yet possesses senses of contact, odor (judging by the thick antenna), and of hearing (it has beautifully developed stridulatory apparatus, which occupies the whole of the large membrane between the postpetiolar and first gastric seg ment°) (Wheeler). This form, as Emery points out, seems to be the nearest of any ants to the Mutillida, especially the genus Apterogy na, which has an ant-like pedicel to the abdo men, and also resembles the ants in other features. That this group is also a very primi tive one is shown by the plastic forms of fe males, of which there are four kinds, signifi cant, as Wheeler remarks, "as the phyletic source to which the different fethale forms of all the subfamilies of ants are to be traced.° Slavery.— This phase of social life is not infrequent among ants, and it reacts upon the slaveholders by rendering them helpless. Formica sanguinea has been observed in Europe by P. Huber to go on slave-hunting expeditions. They attack a colony° belonging to a smaller black species, pillaging the nests and carrying off merely the larva and pupae. The victors educate them in their own nests, and on arriving at maturity the negroes take the entire care of the colony. Polyergus rufescens is also a slave-making ant, and Latreille very justly observes that it is physically impossible for the rufescent ants (P. rufescens), on account of the form of their jaws, and the accessory parts of their mouths, either to prepare habitations for their family, to procure food or to feed them. Formica sanguinels sallies forth in im mensely long columns to attack the negro ant. Huber states that only five or six of these forays are made within a period of a month, at other seasons they rr main at peace. Huber found that the slave-making Polyergus rules tens, when left to themselves, perish from pure laziness. They are waited upon and fed by their slaves, and when they are taken away their masters perish miserably. Sometimes they are known to labor, and were once ob served to carry their slaves to a spot chosen for a nest. The Formica sanguinea are not so helpless; they assist their negroes in the con struction of their nests, they collect their sweet fluid from the Aphides; and one of their most usual occupations is to lie in wait for a small species of ant on which they feed; and when their nest is menaced by an enemy they show their value of these faithful servants by carry ing them down into the lowest apartments, as to a place of the greatest security. Pupa of both the slave-making species were placed in the same formicary by Huber, where they were reared by the anegroes,° and on arriving at ma turity lived together under the same roof in the most perfect amity. Darwin states that in Eng land Formica sanguinea does not enslave other species.