STINGS AND BORERS OF INSECTS. 



91 



Through this the poison flows, which is secreted by a small 

 gland which is situated very near. The sting thus formed is 

 received between a pair of small valves, each composed of two 

 joints, which are enclosed within the last segment of the abdo- 

 men. In a state of repose all these pieces are drawn within the 

 body of the animal ; but when the insect wishes to use it, she 

 causes the dart to project, and buries it in the skin of her enemy. 

 Sometimes it is even impossible for her to draw it out ; the 

 whole sting is then separated from the body, and remains fixed 

 in the wound. The injury which results from this quickly causes 

 the death of the insect. The male is always destitute of this 



weapon ; hence it may be seized 

 without danger : but the females, 

 and generally the sterile indivi- 

 duals, called workers, are pro- 

 vided with it ; the puncture 

 causes a painful inflammation. 

 The borer of the Ichneumons, of 

 theFcenus(F\g. 408), and of many 

 other insects, shows an arrange- 

 ment very analogous, but the 

 parts of which it is composed are 

 generallymuch longer than in the 

 stinging species ; in the Ich- 

 neumons with long ovipositors the organs form three tails, of 

 which the middle one 

 is the true borer, and 

 the others the elong- 

 ated apical joints of 

 the sheathing valves. 

 With the borer the 

 insect pierces the ve- 

 getable or animal tis- 

 sues in which it desires 

 to deposit its eggs, and 



the latter pass through the small canal formed by its three 

 pieces. It is by thus piercing a species of oak, in the Levant, 

 that the small insect, known by the name of Cynips, or Gall-fly, 



FIG. 408.-FCBNUS. 



FIG. 409. THE INK-GALL INSECT, AH,, THE INSECT 

 BY WHICH IT IS PRODUCED. 



