STINGS AND BORERS OF INSECTS. 



91 



flows, that is secreted by a small gland which is situated very 

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

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

 causes the sheath to project, and buries it, together with his dart, 

 in the skin of his enemy. Sometimes it is even impossible 

 for him 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 

 individuals, called workers, are provided with it : the puncture 

 causes a painful inflammation. The borer of the Ichneumons, 

 of the Fcenus (Fig. 308), and of many other insects, shows an 



arrangement very analogous; and 

 we generally observe in it a kind 

 of small saw, by the aid of which 

 the insect pierces the vegetable or 

 animal tissues in which it desires 

 to deposit its eggs. 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, causes the formation 

 of the Gall-nuts, of which so 

 much use is made in the manu- 

 facture of ink, and in the prepara- 

 tion of black dyes. The small puncture effected by the Cynips 

 causes an overflowing 

 of the vegetable juices, 

 and there soon results 

 from this, an excres- 

 cence, in the centre of 

 which we find the eggs, 

 or larvae, of the insect. 

 610. Insects are pro- 

 vided with highly de- 

 veloped senses ; they evidently possess Hearing and Smell, as 

 well as Taste, Sight and Touch; but even now the seat of the sense 



FIG. 308. F(ENUS. 



FIG. 309 THE INK-GAJLL INSECT, AND THE INSECT 



BY WHICH IT IS PRODUCED. 



