268 STATE HORTICULTURAL SOCIETY. 



frequently much injury done before the webs appear. For this reason, I 

 earnestly advocate the destruction of the egg clusters in preference to 

 fighting the insects at a later stage. 



As soon as the caterpillars hatch they move down the twig until they 

 reach another branch; and here in the fork they begin their web. The 

 beginning of such web is represented at d, in the figure just below the clus- 

 ter of eggs. Ordinarily, however, the caterpillars move a much greater 

 distance than that represented, making their web in a much larger fork. 

 This web serves as a nest for the entire colony of worms hatched from the 

 cluster of eggs. As the worms increase in size they add successive layers 

 to the oiitside of the nest, making it larger and larger, until it becomes one 

 or two feet or more in length. 



A point to be remembered is that this web serves merely as a residence, 

 and that the worms must leave it in order to get their food. Thus during 

 a portion of the day comparatively few caterpillars will be found in the nest 

 the majority of them being scattered over the tree, feeding upon the foliage. 

 It is a curious fact that this caterpillar spins a silken thread wherever it 

 goes. As a result of this, there may be found upon the limbs over which 

 the caterpillars pass in going to and from their nest, little bands of silk, 

 extending from their nest to the various parts of the tree where the insects 

 have fed. 



As these webs are very conspicuous, the ordinary method of fighting 

 this insect is by the destruction of it in the webs. This can be easily done 

 by means of a torch attached to the end of a long pole. Care should be 

 taken to do this when the insects are in the web, and not while they are 

 scattered over the trees feeding. Ordinarily the best time will be early in 

 the morning, or late in the afternoon, or during a stormy day. This work 

 should also be done early in the season, very soon after the appearance of 

 the leaves; in fact as soon as the webs can be seen. It is a good deal 

 like locking the stable after the horse is stolen, to delay the destruction of 

 these insects until they are nearly or quite fully grown, as is usually done 

 if done at all. The caterpillars reach maturity about the middle of June. 

 A single mature caterpillar is represented at e, in the figure. At this time they 

 leave the trees in search of a place in which to spin their cocoons; they 

 may then be seen crawling in all directions upon fences and over the 

 ground. They choose some secluded place, as the lower side of a stone or 

 other object, where each makes for itself a dense silken cocoon. Two of 

 these cocoons are represented attached to a piece of wood at h, in the figure. 

 These cocoons may be easily recognized by their having a yellowish-white 

 powder mixed with the silk. 



Within the cocoon the insect changes to a pupa, and remains in this state 

 about three weeks; it then emerges as a brownish moth whose wings are 

 crossed by two oblique whitish lines. This moth is represented at a, in the 

 figure. Soon after the adults appear the females lay their eggs, thus com- 

 pleting the circle of transformations. 



There remains to be mentioned one other method of fighting this insect; 

 that is by spraying the trees, as soon as the leaves appear, with Paris-green 

 water. In this way the caterpillar will be poisoned while feeding upon the 

 leaves. If the apple-tree tent-caterpillar is the only insect to be fought 

 in the orchard, I do not think the spraying of the trees will be found as 

 cheap a method as the destruction of the webs, except in those cases where 

 the insect is very abundant. Ordinarily there will not be more than one 

 or two webs upon a tree; and those can be destroyed much more quickly 



