Page:How to Keep Bees.djvu/236

192 The reproductive organs.—The internal reproductive organs are situated in the abdomen; there is a set on each side, but the two sets open by a common duct, whose outlet is at the hind end of the body.

The reproductive organs of the female are shown on Plate XXVI (a), Fig. 1. There are two ovaries (o), one on each side of the body. Each ovary consists of a large number of parallel egg-tubes, within which the eggs are developed. The egg-tubes of each ovary open into an oviduct (od). The two oviducts unite and form a single tube on the middle line of the body; this is the vagina; the vagina leads to the external opening of the system. Communicating with the vagina, there is a sac-like pouch, the spermatheca, which is the reservoir for the seminal fluid; this is filled at the time of pairing, and the spermatozoa may remain alive in it for several years.

Each egg-tube produces many eggs. As the eggs increase in size, they pass towards the oviduct. When the egg is fully developed a shell is formed about it. This shell has a minute opening through it at one end; this is the micropyle. At the time the egg is laid a spermatozoon may pass from the spermatheca, where thousands of them are stored, into the egg through the micropyle, and thus the egg is fertilised.

With most animals, the egg must be fertilised in order that it may develop. But with bees, both fertilised and unfertilised eggs develop, the former into females, that is, workers or queens, the latter into males, that is, drones.