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190 coating to the eggs before they are extruded. This varnish, however, is more commonly imparted to them in the wider part of the duct, formed by the union of the tubes from the two branches of the ovaries. This common duct is sometimes called the egg-canal. It is of greater diameter than the oviduct and frequently distended in the middle where the egg occasionally remains stationary for a time before being expelled. Of the various appendages of this portion of the egg-conduit, the most important are the sperm-reservoir, (Spermatheca) gluten secretors, and the poison vessels of the aculeate Hymenoptera. The former is a purse-shaped appendage or distention of the duct, destined for the reception of the male influence during copulation, and, according to Herold, the eggs are impregnated in passing it, for it is situate on the upper side, and whenever it opens the sperm flows into the duct. The gluten secretors are commonly more slender, and of a vascular structure, performing the office of a gland. The liquid they secrete is white, and it envelopes the eggs in their passage. Their situation is very close to the sperm reservoir. The poison vessel of the Hymenoptera is an ovate bladder with a narrow duct appended to it, which discharges the contents into the sting.

The vagina is simply the terminating portion of the evacuating duct; a short straight tube, generally a little narrower than the common branch of the oviduct. When an ovipositor exists, the vaginal tube opens directly into it, forming a continuous