I.] METAMORPHOSES OF INSECTS. 7 



having three pairs of legs, and in the former case 

 abdominal pro-legs as well : but in the great majority 

 of Hymenoptera the larvae are legless, fleshy grubs 

 (Plate II., Figs. 7-9) ; and the various modes by which 

 the females provide for, or secure to, them a sufficient 

 supply of appropriate nourishment constitutes one of 

 the most interesting pages of Natural History. 



The species of Hymenoptera are very numerous ; 

 in this country alone there are about 3,000 kinds, 

 most of which are very small. In the pupa state 

 they are inactive, and show distinctly all the limbs of 

 the perfect insect, encased in distinct sheaths, and 

 folded on the breast. In the perfect state they are 

 highly organized and very active. The working ants 

 and some few species are wingless, but the great 

 majority have four strong membranous wings, a cha- 

 racter distinguishing them at once from the true flies, 

 which have only one pair of wings. 



The sawflies are so called because they possess at 

 the end of the body a curious organ, corresponding to 

 the sting of a wasp, but which is in the form of a 

 fine-toothed saw. With this instrument the female 

 sawfly cuts a slit in the stem or leaf of a plant, into 

 which she introduces her egg. The larva much re- 

 sembles a caterpillar, both in form and habits. To 

 this group belongs the nigger, or black caterpillar 

 of the turnip, which is often in sufficient numbers to 

 do much mischief. Some species make galls, but 

 the greater number of galls are formed by insects 

 of another family, the Cynipidae. 



In the Cynipidae (Plate I., Fig. 7) the female is 

 provided with an organ corresponding to the saw of 



