136 WASPS [CH. V 



and down within the director but cannot be separated 

 from it nor drop out from the groove. 



At its anterior end the " director " is enlarged and its 

 groove widened: at this point 

 the needles become free from 

 the inturned flange but are still Srud8 . 

 kept in contact and parallel 

 with the margin of the "di- 

 rector" by a double series of 



peculiar hairs (OH}, about 50 tlae region of the letter D, 



in Fig. 24. 



in number, situated on its 



inner face near the ventral edge. The outer edge of the 

 needle runs between the upper and lower series of hairs 

 and is thus retained in position. Within the tapering 

 part of the director the hairs are replaced by studs (GS). 

 These cluster in a group at first, but in the narrower 

 parts of the director are isolated and rather irregularly 

 disposed. They serve to guide the needles in their passage 

 through the director. There is no continuous "bead" such 

 as Carlet describes as performing this function in the 

 sting of the honey-bee. 



Anteriorly the needles diverge from one another and 

 bend rather sharply in a dorsal direction. Between them 

 is interposed a bulbous muscular mass (not shown in the 

 figure) attached to the anterior end of the director. 

 Finally the needles are articulated to strong levers LN, 

 LN' which give attachment to powerful muscles. When 

 the handle of the lever is pulled down by these muscles, 

 in the direction shown by the arrows in the figure, the 

 arm which articulates with the needle is thrust backward 



