THE HYMENOPTERA. 223 



peculiar poison-glands are superadded, which render 

 it a most formidable offensive weapon. The ovipo- 

 sitor, in its most perfect form, consists of three 

 bristle-like valves, one above and two below, the 

 superior one being- channeled throughout its whole 

 length for the reception of the two lower ones, which 

 are curiously serrated or barbed towards the tip. 

 These two lower bristles, however, do not occupy 

 the whole of the channel in the lower surface of their 

 larger companion, but leave a small vacant space in 

 the centre ; so that the three pieces, when fitted toge- 

 ther, form a narrow tube, through which the egg can 

 pass into the wound made by this compound borer. 

 Besides these bristles, we find within the aperture, at 

 the apex of the abdomen, a pair of small horny valves 

 composed of two joints, of which the first is always 

 concealed, whilst the second, which is usually as long 

 as the ovipositor itself, projects along with this when 

 it is exserted, and serves as a sort of sheath to the 

 weapon. The ovipositor undergoes various modifica- 

 tions of structure in the different groups, and in the 

 very first tribe we shall find that there is some little 

 difficulty even in referring this organ to the above 

 type, but in the majority it is formed precisely upon 

 the plan just described. 



As already stated, the metamorphosis of the Hyme- 

 noptera is complete, as complete in fact as that occur- 

 ring amongst the Coleoptera or any other order of 

 insects. The larvae of the majority are mere footless 

 grubs, more helpless even than the well-known mag- 

 gots of the Dipterous flies, like which they feed upon 

 substances in the midst of which the eggs have been 

 laid by their parents, whilst in some instances the 

 females feed the young and tend them with the great- 



