The working bees form by far the most numerous of the three classes contained in the hive. They are the smallest of the bees; in colour they are dark brown or nearly black (except the Italians and other foreign varieties), and they are distinguished by their activity upon the wing. As to their numbers in a colony, "an ordinary first swarm from a straw hive," says Von Berlepsch, "contains from twelve to twenty thousand, but I have had large wood hives in which, at a moderate computation, there were living at the end of June about a hundred thousand bees:" from thirty to fifty thousand, however, will better represent the strength of an average stock in an English hive. The worker, though formerly spoken of under the term "neuter," is of the same sex as the queen, but is only partially developed, and thus, with some exceptions (see § ix.), it is incapable of laying eggs. But any egg which would ordinarily produce a worker bee may, by the cell being enlarged and the "royal jelly" supplied to the larva, be hatched into a mature and perfect queen. This most curious fact may be verified in any apiary by most interesting experiments, which are capable of being turned to important use. The lives of the worker bees vary very greatly, and are much more prolonged during the repose of winter than in the wear and tear of the gathering season. Von Berlepsch describes three careful sets of experiments which he carried out for the purpose of attaining more exact knowledge on this point. In one of these he introduced an Italian queen into an ordinary stock at the beginning of October when all the old brood was hatched; he then found as a result that the last of the common bees had disappeared at the end of May, so that some of them for a certainty lived eight months, and possibly more, though it seems most probable that the last to die were also the latest born. In another case, the queen having died at the commencement of winter, he strictly isolated the hive, and, the season being exceptionally mild, he found that some of the bees continued alive for _ten and a half months_. His remaining experiment bore upon the summer term of existence, and it resulted in exhibiting _six weeks_ as the _average_, and three months as the outside possible period of lifetime. Dzierzon points out the difference produced by the character of a bee's employment. To have to fly a long distance to its pasturage will soon wear it out, and so will knocking its wings against sharp leaves, as is the case with the bluebottle, the thick corn amid which this plant grows rendering the effect very much worse. But if, he adds, they pass the summer in entire repose, as a hive without a queen may do, then, if well fed, their lives may be prolonged for _a year or even more_.