54 



INSECTS INJURIOUS TO THE APPLE. 



Fig. U. 



pale-bluish color, sprinkled all over with black i)(>iuts and 

 dots. On the back is a row of" ten or eleven oval or diamond- 

 shaped white spots, by which it may be at 

 once distinguished from tiie common tent- 

 caterpillar, while on the sides there are pale- 

 yellowish stripes, somewhat broken, and 

 mixed with gray. The hairs on the body are 

 fox-colored, mixed with coarser whitlsli hairs. 

 The caterpillars attain full growth about the 

 middle of June. 



Occasionally, during the latter part of 

 May, when about iialf grown and extremely 

 voracious, these larvae will appear in per- 

 fect swarms and attract general attention. 

 During the latter part of the day, and fre- 

 quently also in the morning, they collect on the trunks and 

 larger branches of the trees in large black masses, which are 

 so easily reached that they seem to invite destruction. While 

 j)articularly injurious to the apple, they also attack various 

 species of forest-trees, such as oak, thorn, ash, basswood, beech, 

 plum, cherry, walnut, hickory, etc., and sometimes large 

 clumps of wood may be seen in June quite bare of" foliage 

 from the devastation caused by this insect, while underneath 

 the ground is covered with small black grains of exuvia. 

 It is often very abundant in the West, and occasionally equally 

 destructive in the South, especially in Georgia and Tennessee. 

 When full grown, this larva spins a cocoon (see Fig. 45) 

 closely resembling that of the tent-caterpillar, usually within 

 the shelter of a leaf, the edges of which are partly drawn 

 togetlier. Within such an enclosure there is generally one 

 cocoon, but in times of great abundance, and where the en- 

 closure is large enough, there are often two or three cocoons 

 together. At such periods almost every leaf or fragment of 

 a leaf is so occupied, and, the whitish-yellow cocoons being 

 only partly hidden, and the leaves hanging with their weight, 

 one is impressed with the idea that the tree is laden with some 



