. The Cambridge natural history. Zoology. ACULEATAy—DEVELOPMENT. (Fig. 4, A) placed two on the one, four on the other ; these are the rudiments of the sting. In the course of development the terminal three segments are taken into the body, and the external pair of the appendages of the twelfth !«>dy segment (the ninth abdominal) become the sheaths of the sting, and the middle pair become the director; the pair of appendages on the eleventh segment give rise to the needles or spiculae. The sting-rudiments at an earlier stage (Fig. 4, C) are masses of hypodermis connected with tracheae; there
. The Cambridge natural history. Zoology. ACULEATAy—DEVELOPMENT. (Fig. 4, A) placed two on the one, four on the other ; these are the rudiments of the sting. In the course of development the terminal three segments are taken into the body, and the external pair of the appendages of the twelfth !«>dy segment (the ninth abdominal) become the sheaths of the sting, and the middle pair become the director; the pair of appendages on the eleventh segment give rise to the needles or spiculae. The sting-rudiments at an earlier stage (Fig. 4, C) are masses of hypodermis connected with tracheae; there is then but one pair on the twelfth segment, and this pair coalesce to form a single mass; the rudiments G of the pair that form the director are FlG. 4.—Development of sting of differentiated secondarily from the the bee: A and C, ventral; B, side view. A, End of abdomen primary pair ot these masses 01 hypo- dermis. A good deal of discussion has taken place as to whether the component parts of the sting— gonapophyses—are to be considered as modifications of abdominal extremities ( abdominal legs such as exist in Myriapods). Heymons is of opinion that this is not the case, but that the leg-rudiments and gonapophysal rudi- ments are quite The origin of the sting of Hymenoptera (and of the ovipositor of parasitic Hymenoptera) is very similar to that of the ovipositor of Locusta (Vol. V. p. 315 of this work), but there is much difference in the history of the development of the rudiments. Dewitz has also traced the development of the thoracic appendages in Although no legs are visible in the adult larva, they really arise very early in the larval life from masses of hypodermis, and grow in the interior of the body, so that when the larva is adult the legs exist in a segmented though rudimentary condition in the interior of the body. Dewitz's study of the wing-development is less complete. i. Jahrb. xxiv. 1896, p. 192. - Zeitscltr. iciss. Zool
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