COMPOSITION OF THE GVIPOSITOK. 



17 



Fiir. 2:i. 



of thin lamellifonn pieces of sixiiilnr form uiid stiuclure, arising 

 from the sternite of tlie ninth ring. These outgrowths appar- 

 ently also homologize witli the flhlbrm, antennte-lilie, jointed 

 appendages of tlie eleventh ring, as seen in the Perlidaa and 

 most Neuroptcra and Orthoptera (especially in Mantis tes- 

 selJuta Avhere they (Fig. 23) closely 

 resemble antennie), which, arising as 

 they do from the arthropleural, or limh- 

 bearing region of tlie body, i. e. between 

 the sternum and episternum, are strictly homologous with the 

 abdominal legs of the Myriapoda, the ''fajse legs" of cater- 

 pillars, and the abdominal legs of some Neiiroptei'ous larvne 

 {Corijddli.s, Fhryganeidce, etc.). 



It will thus be seen that the attenuated form of the ti[) is 

 produced by the decrease in size of certain parts, the actual 

 disappearance of others, and the perfection of those parts to 

 be of future use. Thus towards the extremity of the body 

 the pleurites are absorbed and disappear, the tergites overlap 

 on the sternites, and the latter diminish in size and are 

 withdrawn within the body, while the last, or eleventh sternite, 

 entirely disappears.* Meanwhile the sting grows larger and 



larger, until finally we 

 have the neatly fashioned 

 abdominal tip of the bee 

 concealing the coni[)lex 

 sting with its intricate 

 system of visceral ves- 

 sels and glands. 

 The ovipositor, or sting, of all insects, therefore, is formed 

 on a common plan (Fig. 24). The solid elements of tlie artliro- 



*In lidndirn, however, I.acaze-Dutliicrs has noticed the curious fact that in 

 order to forni the long rcsiiiiMtory tube of this insect, the tergite and sternite of the 

 ))rcgenital (eighth) segment are aborted, while the ideurites are enormously en- 

 larged and elongated, so as to carry the stigmata far ont to the end of the long tube 

 thus formed. 



Fig. '2.5. End of the abdomen of Sfantis teK.<cllafa : p, many-jointed an*l style 

 resembling an antenna. 5-11, the last seven abdominal segments: the f<-llth ster- 

 nites being obsolete. — From Lucaze-T)utkiers. 



Fiu. 24. Ideal plan of the structure of the ovipositor m the adult insect. l-Ti, 

 the tergites, connected by dotted lines with then* c<)rres|)onding sternites. h, the 

 eighth tergite, or anal scale; c, epimerum; a', a. two pieces forming the outer pair 

 of rhabdites; «, the second pair, or stylets; and ./". the inner pair, or sting; </, the 



2 



