These, called "the bees," by Aristotle, and even by Wildman and Bevan, are by far the most numerous individuals of the hive--there being from 15,000 to 40,000 in every good colony. It is possible for a colony to be even much more populous than this. These are also the smallest bees of the colony, as they measure but little more than one-half of an inch in length (Fig. 19). [Illustration: Fig. 19. _Worker-Bee, magnified._] The workers--as taught by Schirach, and proved by Mlle. Jurine, of Geneva, Switzerland, who, at the request of Huber, sought for and found, by aid of her microscope, the abortive ovaries--are undeveloped females. Rarely, and probably very rarely, except that a colony is long or often queenless, as is frequently true of our nuclei, these bees are so far developed as to produce eggs, which, of course, would always be drone eggs. Such workers--known as fertile--were first noticed by Riem, while Huber actually saw one in the act of egg-laying. Except in the power to produce eggs, they seem not unlike the other workers. Huber supposed that these were reared in cells contiguous to royal cells, and thus received royal food by accident. The fact, as stated by Mr. Quinby, that these occur in colonies where queen-larvæ were never reared, is fatal to the above theory. Langstroth and Berlepsch thought that these bees, while larvæ, were fed, though too sparingly, with the royal aliment, by bees in need of a queen, and hence the accelerated development. Such may be the true explanation. Yet if, as some apiarists aver, these appear where no brood has been fed, and so must be common workers, changed after leaving the cell, as the result of a felt need, then we must conclude that development and growth--as with the high-holder--spring from desire. The generative organs are very sensitive, and exceedingly susceptible to impressions, and we may yet have much to learn as to the delicate forces which will move them to growth and activity. Though these fertile workers are a poor substitute for a queen, as they are incapable of producing any but drones, and are surely the harbingers of death and extinction to the colony, yet they seem to satisfy the workers, for they will not brook the presence of a queen when a fertile worker is in the hive, nor will they suffer the existence in the hive of a queen-cell, even though capped. They seem to be satisfied, though they have very slight reason to be so. These fertile workers lay indifferently in large or small cells--often place several eggs in a single cell, and show their incapacity in various ways. [Illustration: Fig. 20. _Tongue of a Worker-Bee, much magnified._] _a_--Ligula. _c, c_--Maxillæ. _b, b_--Labial palpi. _d_--Paraglossæ. [The average length of a black worker's tongue, as compared with this from an Italian, would be from base to _a_.]