Injurious Insects and How to Control Them. 63 



well to go slow before trying it. One of tlie oldest fakes is plug- 

 ging trees with sulphur or some other substance said to be taken 

 up by the sap, thus rendering the foliage distasteful to insect 

 pests. Such claims have no foundation and should not be heeded. 

 Yet in 1896 or thereabout, as stated to me by Mr. E. Van 

 Alstyne, such an agent appeared in Kinderhook, N. Y., charged 

 two dollars for plugging a tree, took in about |50 and then de- 

 parted, leaving an unpaid board bill. 



Insect changes. — The farmer should also have some general 

 knowledge of the transformations of insects in order that he may 

 recognize both friends and foes in their various stages. All in- 

 sects develop from eggs of one form or another, though in some 

 cases the eggs hatch within the body of the parent. The larva is 

 the active, growing form, and is the stage more frequently de- 

 structive. It is variously known as the caterpillar, grub, maggot, 

 " worm," etc. The pupa is the quiescent, resting stage, during 

 which the transformation from the comparatively simple cater- 

 pilar to the highly organized butterfly or moth takes place. 

 These changes will be more fully emphasized in the following 

 accounts of certain injurious species: 



Apple tree tent caterpillar. — This insect, Clisiocampa americanu, 

 yearly causes much damage in spite of the fact that its habits 

 are well known and methods of suppressing it are understood. It 

 passes the winter in the egg. The brownish egg mass encircling 

 a twig is represented at figure 1 on plate 1. The young cater- 

 pillars may be found well developed within the egg in the fall 

 and emerge therefrom in early spring. They remain in clusters 

 under the familiar tent, feeding on adjacent foliage, and by the 

 time they are half grown, we have the well-known condition 

 represented at figure 3, plate 1. The caterpillars become full 

 grown (plate 1, figure 2) the latter part of May, and at that time 

 may be seen wandering in all directions, seeking a place for 

 spinning their cocoons, several of which are represented at figure 

 6, plate 1, and one still more enlarged at figure 4. The co- 

 coons are spun in early June and may be found in almost any 



