The anal cerci are present in the Orthoptera and, when multiarticulate, function as abdominal antennæ. They are longest in the Mantidæ (Fig. 182); they also occur in the larva of the saw-fly, Lyda (Fig. 183). Dr. A. Dohrn has stated that the cerci of Gryllotalpa are true sensory organs, and we have called those of the cockroach abdominal antennæ, having detected about ninety sacs on the upper side of each joint of the stylets, which are supposed to be olfactory in nature, and which are larger and more numerous than similar sacs or pits in the antennæ of the same insect.[36] From his experiments upon decapitated cockroaches, Graber concluded that these cerci were organs of smell. [Illustration: FIG. 183.—Lyda larva: _a_, head; _b_, end of body seen from above; _c_, from side, with cercopod. ] Haase regarded these appendages, from their late development and frequent reduction, as old inherited appendages which are approaching atrophy through disuse. Cholodkowsky states that Tridactylus, a form allied to Gryllotalpa, bears on the tenth abdominal segment two pairs of cerci (ventral and dorsal), and that the ventral pair may correspond to the atrophied appendages of the tenth embryonic segment of Phyllodromia, with which afterward the eleventh segment becomes fused. The cercopods are not necessarily confined to the eleventh or to the tenth segment, for when there are only nine segments, with the vestige of a tenth, as in Xiphidium, they arise from the ninth uromere, and in the more modern cockroaches, as Panesthia, in which there are but seven entire segments, they are appended to the last or eighth uromere. [Illustration: FIG. 184.—Anabrus, ♀, side-view, dissected; showing the relative size of the ovipositor: _c_, the minute cercopod.—Kingsley _del._ ] As to the homology and continuity of these cercopods with the ventral outgrowths of the embryo, several embryologists, notably Wheeler, are emphatic in regarding them as such. It thus appears that either the embryonic appendages of the seventh or eighth, ninth or tenth uromere may persist, and form the cercopoda of the adult. =The ovipositor.=—The end of the oviduct is guarded by three pairs of chitinous, unjointed styles closely fitted together, forming a strong, powerful apparatus for boring into the ground or into leaves, stems of plants, the bodies of insects, or even into solid wood, so that the eggs may be deposited in a place of safety. In the ants, wasps, and bees the ovipositor also functions as a sting, which is further provided with a poison-sac.