THE APPLE-TREE CATERPILLAR. 



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793. Ichneumon-flies are of various species and dimen 

 sions, but they all have four wings of membranous 

 texture, and the general appearance of a wasp. Some 

 of them pierce the eggs of other insects and deposit 

 their own within them ; others insert them beneath the 

 skin of a living caterpillar, where they hatch into little 

 maggots, which devour its flesh and soon put an end to 

 its life. Figure 52 represents a species (natural size and 

 magnified) which deposits its eggs in the body of the 

 common grape-vine caterpillar. Figure 53 shows the 

 caterpillar after the maggots of the ichneumon have 

 finished eating and, returning through the skin of the 

 caterpillar, have spun their cocoons upon its surface. 



Fig. 51. Fig. 53. 



794. The apple-tree caterpillar may be guarded 

 against by carefully removing all the nests as soon 

 as perceived, and crushing both larva) and nests. 

 If this practice be well followed up, they may be 

 eradicated from a whole neighborhood. A round 

 brush fixed to the end of a long pole is the most 

 convenient instrument for reaching the nest. The eggs, 

 (Fig. 54,) which are laid the previous season, may be 



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