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TEXT-BOOK OF ENTOMOLOGY 



Kraepelin and Bugnion observed a pair of rudiments to each of the 

 three penultimate segments, those of the middle pair splitting in two. 

 Wheeler maintains, erroneously we think, that the inner of the two 

 pairs on the ninth segment represents the 

 tenth pair of abdominal appendages ; but in 

 reality this latter pair become the cercopods. 

 That there are probably originally in insects 

 of all the orders provided with an ovipositor 

 three distinct pairs of appendages, one to 

 each segment, is proved, or at least strongly 

 suggested, by Ganin's researches ; on the 

 three pairs of abdominal imaginal discs of 

 the third larva of Platygaster and Polynema 

 (Fig. 188), which are transformed into the 

 ovipositor. He remarks that these imaginal 

 discs have the same origin and pass through 

 the same changes as those in front, i.e. 

 those destined to form the thoracic legs. 

 Dewitz has shown that the germs of the 

 ovipositor of the honey-bee arise as buds 

 FIG. 188. Third larva of on the two segments before the last (Fig. 



Polynema : at, antenna ; ft, im- -i OQ\ 



aginal buds of the wing; I, of J Ot V g 



the legs ; Ig, buds of the middle Kvapnplin aln rlptpptprl in fhp lavva nf 



pair of stylets of the ovipositor ; ^ ae P el 



^A f fter^a y n ; in (7 ' ear " Iikeprocess ' the honey-bee a pair of what he regarded 

 as genuine imaginal buds on abdominal seg- 

 ments eight, nine, and ten ; the buds on the tenth segment are divided 

 each in two ; of these four appendages the two median ones form the 

 barbed sting (gorgeret or stachelrinne), and the two lateral stylets, 



23. 



FIG. 189. Imaginal buds and papilla? of the ovipositor of the honey-bee attached to trachea- ; 

 at different stages : b', 1st; ?/', 2d or middle ; and c , 3d pair of papilla- ." Ai'tt-i Dewitz. 



the valves (stachelscheiden). The two buds of the ninth segment 

 give rise to the vagina and to the oviducts, and these unite second- 

 arily with the posterior end of the ovaries. The genital appendages 



