CH. V] 



WASPS 



135 



and two three-sided " needles " bearing six barb-hooks at 

 their apices. The "director" tapers posteriorly and is 

 rounded dorsally so as to form rather more than a half- 

 cylinder: on its ventral face is a deep groove in which 

 the needles slide to and fro : and the edges (E) of the 

 groove are turned in so as to receive the outer ridges of 

 the needles right and left. The whole may be compared 

 to an inverted gutter-pipe with a flange turned in 

 partly closing the concavity and lodging two rods within 

 it (vide Fig. 24). The needles can thus slide freely up 



L.N 



N.P 



Fig. 24. Ventro-lateral view of sting of Vespa germanica ? : the needle 

 of the far (right) side has been withdrawn and is shown below the 

 other structures. 



D. Director. E. Ventral inturned edges of director. G.H, G.H'. 

 Guiding hairs of left and right sides. G.S. Guiding studs on 

 inner face of D. L.D, L.D'. Levers of left and right sides for 

 extrusion of D. L.N', L.N. Levers for extrusion of left and right 

 needles, N', N, beyond tip of D. N. Eight needle withdrawn 

 from D but lying parallel to its original position. N'. Anterior 

 part of left needle ; the remainder lies concealed within D. N.P, 

 N.P'. Piston (?) enlargements on right and left needles. S. Stout 

 ehitinous piece on dorsal surface of D. The arrows show the 

 direction in which the muscles pull the levers when the sting is 

 employed. The poison sac and duct are not shown. 



