56 



INSECTS INJURIOUS TO THE APPLE. 



bands should be tied tightly in the middle. Each caterpillar 

 is furnished with four pairs of fleshy prolegs^ which are 

 fringed with small horny hooks, and on the insect's trying 

 to pass over the cotton these hooks get so entangled in the 

 fibres that further progress becomes Very difficult, and is 

 seldom persisted in. A shower of rain will pack the fibres 

 of the cotton somewhat, but where the string fastening it is 

 tied around the middle, the upper half washes down and 

 makes a sort of roof overhanging the lower portion, which in 

 great measure protects it from the weather. 



These larvae are seldom abun- 

 dant for many years in succession, 

 for in times of great plenty their 

 natural enemies multiply with 

 ->^ amazing rapidity. Several par- 

 asites destroy them. Two species 

 of Ichneumon flies prey on them, 

 also a two-winged Tachina fly, 

 closely resembling the Red-tailed 

 Tachina fly, Nemoreea leucaniee (Kirkp.) (Fig. 46), which 

 attacks the army-worm, but this fly is without the red tail. 



Fig. 46. 



Fig. 47. 



Fig. 48. 



A species of bug (Hemiptera) attacks the larvae just when 

 they are constructing their cocoons, and sucks them empty. 



