78 



INSECTS INJURIOUS TO THE APPLE. 



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 or on 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 larvse 

 perish in this manner. The 

 largest of these parasites, 

 and perhaps the commonest 

 of them all, is the Long- 

 tailed Ophion, Ophion ma~ 

 a'urwii (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 larvae soon hatch, and, having firmly 

 attached themselves, feed externally, sucking the juices of the 

 caterpillar. After the latter has attained full growth, formed 



its cocoon, and become a 

 ^^^- '^*- chrysalis, this useful para- 



site causes its death. When 

 \ /~~\ full grown, the larva of the 



parasite is a large, fat, foot- 

 less grub (Fig. 74), which 

 spins an oblong-oval cocoon 

 within the Crecopia 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 



