168 TEXT-BOOK OF ENTOMOLOGY 



" One embryo, which had just completed katatrepis, still showed traces of all 

 the abdominal appendages. The pairs on the eighth, ninth, and tenth segments 

 were somewhat enlarged. In immediately succeeding stages the appendages of 

 the second to sixth segments disappear ; the pair on the seventh disappear some- 

 what later. Up to the time of hatching the gonapophyses could be continuously 

 traced, since in Xiphidiurn there is no flexure of the abdomen, as in other 

 forms, to obscure the ventral view of the terminal segments. From the time 

 of hatching Dewitz has traced the development of the ovipositor in another 

 locustid (Locitsta viridissimci) , so that now we have the complete history of the 



Heymons, however, is inclined to believe that they are simply 

 hypodermal outgrowths. 



The first to study the morphology of the ovipositor was Lacaze- 

 Duthiers, who referred their origin to the partially atrophied dorsal 

 or ventral sclerites of one of the last abdominal segments; a view 

 accepted by Gerstaecker 1 (Figs. 186, 187). The present writer (1866), 

 however, showed that the sting of Bombus was not formed of the 

 reduced pieces of the segments themselves, but arose from special 



outgrowths on the ventral 

 side of the eighth and ninth 

 abdominal segments. These 

 appendages he did not at first 

 regard as the homologues of 

 the limbs, until in 1871, after 



FIG 1S6 Ideal plan of the structure of the ovi- studying the Origin of the 



X ^Si spring of the Podurans (Iso- 



pairfo^g^sSpporT K% ;t toma), he f OUlld that it was a 

 piece supporting the stylet ; .fi, amis; o, outlet of ovi- , -iniiitprl Fmnpnrlicrp qnrl 



duct. The Tth, 8th, and 9th. sternites are aborted. - 3 JO1HW L appe 



After Lacaze-Duthiers. therefore a homologue of a 



pair of the styles forming the ovipositor of the winged insects, 

 and that the three pairs of styles of the latter were homologues 

 of the thoracic legs and cephalic appendages. The view was 

 stated in the Guide to the Study of Insects. (See also Amer. Nat., 

 March, 1871, p. 6.) Kraepelin also affirms that the styles of the 

 ovipositor are segmental appendages and homologues of the antennae, 

 wings (sic), and legs. 



An objection to this view is the fact that the posterior pairs of 

 styles appear to arise both from one and the same segment, the 

 ninth. Dewitz questions whether the four appendages of the ninth 

 segment represent two pairs of limbs, or one pair split into two 

 branches, and prefers the latter view, but leaves it as a point to 

 be settled by future investigations. As will be seen below, both 



i Handbuch der Zoologie, p. 17, 1863, Fig. 1G2. 



