Page:Jardine Naturalist's library Entomology.djvu/195

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
OF INSECTS.
189

destined for the propagation of the species, may be said to have a general correspondence with those of the higher animals. They occupy the hinder part of the abdomen, and the external organs pass out by a distinct outlet, lying a little below the orifice of the alimentary canal. In the female, the following organs exist; the ovaries, oviduct, and vagina; besides various peculiar parts, as well as certain exterior appendages designed to convey the eggs in safety to their nidus, or to act as instruments of defence, termed ovipositor and sting.

The ovaries are membranous tubes or bags in which the eggs are generated, and where they remain till they acquire a considerable size. They are divided into two pretty equal portions, one lying on each side of the abdomen. Their shape is very variable, but most of them may be referred to the three following types of form. 1. Simple bags, containing the germs of the eggs. 2. Short ovaries, thickly placed over the surface of a large bag-shaped common ovarium. 3. Long tubular ovaries, containing many eggs, resembling a necklace, either entirely free, or united by a loose cellular tissue.

The oviduct is the canal which emanates from each half of the ovarium, and which both unite in the median line of the body, and form a common evacuating or ejaculatory duct. The length and capacity of these canals vary greatly. Sometimes they are supplied with glandular appendages, for the purpose of elaborating a glutinous matter, which forms a