Ovipositor

ovipositor [′ō·və‚päz·əd·ər]

(invertebrate zoology)

A specialized structure in many insects for depositing eggs.

(vertebrate zoology)

A tubular extension of the genital orifice in most fishes.

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Ovipositor 

the external sexual organ in the females of many insects and some fish (for example, Rhodeus) by means of which eggs are laid. The ovipositors of insects are modified appendages to the eighth and ninth abdominal segments. They consist of three pairs of valves with the sexual orifice located between their bases. The valves of the ovipositor penetrate the substrate, and the eggs slide down between the valves during egg laying.

Because the eggs of Acrididae are placed into the soil in sacs that must be deposited at great depths, the ovipositor is strong and short and acts as a digging apparatus. The abdomen of the Acrididae can become elongated in order to push down the ovipositor. In dragonflies, true bugs, cicadas, and sawflies, the ovipositor places the eggs into plant tissue. Ichneumon flies and other hymenopterans have a long and sharp ovipositor that introduces eggs into the bodies of other insects, where the larvae live as parasites. The ovipositors of higher hymenopterans (honeybees, wasps, bumblebees) have become stingers—organs of protection and attack.

In fish the ovipositor is a modified urogenital papilla, which becomes elongated during spawning.

A. V. IVANOV