COMPOSITION OF THE OVIPOSITOR. 



15 



complete pupa of the Humble-bee, and other thin-skianed 

 Hymenopterous larvoi, and in a less satisfactory Avay in the 

 young Dragon-flies. 



If the larva of the Humble-bee be taken just after it has 

 become full-fed, and as it is about to enter upon the pupa state, 



the elements 



a a 



o o <:iD,c::> 



(sterno- rhab- 

 dites Lacaze- 

 Duthiers), or 

 tubercles, 

 destined to 



Fi-. IG. 



form the ovipositor, lie in 

 separate pairs, in two groups, 

 Fig. 11. Fig. 15. exposed distinctly to view, 



as in Figures 14-18. The ovipointor thus consists of three 

 pairs of slender non-articulated tubercles, situated in juxta- 

 position on each side of 

 the mesial line of the 

 body. The first pair arises 

 from the eighth abdominal 

 ring, and the second and 

 third pair grow out from 

 the ninth ring. The ends 

 of the first pair scarcely 

 reach beyond the base of 

 the third pair. AVith the 

 growth of the semi-pupa, 

 the end of the abdomen 

 decreases in size, and is 



Fig. 14. Rudiments of the sting, or ovipositor, of the Humble-bee. 8, 9, 10, 

 stcruites of cightli, ninth, anil tenth abdominal rings in the larva, a, first pair, .situ- 

 ated on the eighth sternite ; b, second and inner pair ; and f, the outer pair. The let- 

 tering is the same in figures 14-2-2. The inner pair (b), forms the true ovipositor, 

 thiough which the eggs are supposed to pass when laid by the insect, the two 

 outer pairs, a and o, sheathing the inner pair. Ganin sh!)ws tliat in the embryo oi 

 PoIynemuiFig. G.j.5), the throe pairs of tubercles arise from tho 7tli, 8th and 9th s'g- 

 meuts respectively. Fig. 1.5,10. The same a little f.irther advanced. 



Fig. 17. The three pairs now iippear as if together growing from tho base of the 

 ninth segment; 17n, side view of the same, showing the end of the abdomen grow- 

 mg smaller through the diminution in size of the under side of the body. 



Fig. 18. The three pairs of rhabdites now nearly equal in size, and nearly 

 ready to unite and form a tube; ISa, side view of the same; the end of the abdo- 

 men still more pointed; the ovipositor is situated between the seventh and tenth 

 rings, and ia partially retracted within the body. 



18 a. 



