INSECTS INJURIOUS TO THE APPLE. 



Fig. 73. 



prevents the proper ripening of the wood, and often endangers 

 the life of the tree. 



Remedies. — The natural increase of this insect is great, and 

 wise provisions have been made to keep it within due bounds. 

 Being so conspicuous an object, it often forms a dainty meal 

 for the larger insectivorous birds ; there are also enemies 



which attack the egg and 

 young larva, and several 

 species of parasites which 

 live within the body of 

 the caterpillar, and finally 

 destroy it either in the lar- 

 val or the chrysalis state: 

 it is believed that fully 

 four-fifths of the larvae 

 perish in this manner. The 

 largest of these parasites, 

 and perhaps the commonest 

 of them all, is the Long- 

 tailed Ophion, Ophion ma- 

 cniruiii (Linn.) (Fig. 73), a large, yellowish-brown Ichneumon. 

 The female of this fly deposits her eggs on the skin of her 

 victim, where the young larvse soon hatch, and, eating their 

 way to the interior, prey upon the fatty portions of the cater- 

 pillar. After the latter has attained full growth, formed its 



cocoon, and become a chrys- 

 alis, the enclosed parasite 

 causes its death. When full 

 grown, the larva of this par- 

 asite is a large, fat, footless 

 grub (Fig. 74), which spins 

 an oblong-oval cocoon with- 

 in the Cecropia chrysalis, and escapes as a fly, sometimes in 

 the autumn, but more frequently in the following spring. 

 A two-winged fly, a species of Tachina (Fig. 46), is also very 

 frequently found as a parasite on the caterpillar. The larva 



Fig. 74. 



