Page:Popular Science Monthly Volume 64.djvu/108

104 roots of the grape, is as follows: A series of parthenogenetic wingless females succeed each other, until at the end of June the last generation of these produces, parthenogenetically, winged females that are capable of migrating. These also produce parthenogenetic eggs of two kinds, small ones from which winged males develop, and larger ones from which winged females arise. Union of the sexes now takes place and each female lays one egg which gives rise in the following spring to the parthenogenetic wingless female that lives on the root of the grape vine.

We come now to the much discussed case of the hive bee. There are here three kinds of individuals: the queen which lays all the eggs; the workers, which are immature females and do not reproduce at all, and the drones or males which fertilize the eggs of the queen.

It has long been believed that when an egg of the queen is fertilized it gives rise to a female (either queen or worker according to the kind of food given to the young maggot), but if not fertilized the egg gives rise to a male. It has been generally assumed, in accordance with this belief, that all the eggs are alike and will produce males if they are not fertilized, but females if they are fertilized. It is known moreover that the cells of the comb in which the queen deposits the eggs that are to become males are different from the worker cells, and this fact is generally interpreted to mean that the queen is capable of determining the sex of her offspring by allowing or preventing the fertilization of the egg. The sperm which was received by the young queen at the time when she left the hive with a swarm is stored up in a special sac or receptacle with muscular walls and an outlet that opens near the oviducts. It is generally assumed that the queen squeezes out the sperm when an egg that is to be fertilized is laid, but does not do so when a male is to be produced. Some writers have marveled at this wonderful power, that seems almost akin to intelligence, by which the queen determines 'at will' the sex of her offspring, but this may give an entirely exaggerated idea of what takes place, for the act may be a very simple reflex. It has been shown by Drory that if the queen is supplied with an artificial comb containing only drone cells she may be forced to lay in them fertilized eggs that become workers. Conversely, if supplied with worker cells only she will sometimes lay unfertilized eggs in them. This has been interpreted to mean that there are really two kinds of eggs that are laid by the queen, male and female, and that only the latter are capable, as a rule, of being fertilized. On this assumption we should be forced to conclude either that the queen can determine which kind of egg is to be laid and places it in its proper cell, or that she has a knowledge