53 



Occasionally, the cocoons are attached to the smaller twigs, and in 

 such cases a leaf is usually involved, making these places more 

 noticeable during the winter. 



The eggs hatch in the spring and the caterpillars feed on the 

 leaves, becoming full grown in June. They then go to the trunk or 

 larger limbs, where they spin gray cocoons from which the moths 

 emerge in July. 



The female moths, being without wings, remain on the cocoons 

 from which they emerge and there lay their eggs, covering them with 

 white froth as already described for the preceding brood. These 

 eggs soon hatch and the caterpillars climb to the leaves and feed 

 until the middle or last of August ; then, when full grown, return to 

 the trunk or larger branches to make cocoons in their turn, the 

 moths from these emerging shortly thereafter and laying eggs, which 

 remain through the winter before hatching. 



This sketch of the life history shows that there are two broods of 

 the insect each year, and consequently two periods of injury to the 

 trees, the first being during the spring months and ending in June ; 

 the second being during July and August. When the caterpillars 

 are so abundant as to strip the tree in the spring, the second brood 

 will appear in time to feed on the new growth put out by the tree to 

 replace that lost earlier, thus seriously injuring it by more or less 

 completely defoliating the tree twice in the same year — a drain which 

 no tree can successfully withstand for more than a year or two. 



Treatment for the Tussock Moth may be of two kinds. If the 

 caterpillars are already at work on the leaves, spraying with arsenate 

 of lead is effective ; but a simpler and cheaper method for their con- 

 trol is to gather and destroy the egg masses, this being made easier 

 by the presence of the white crust over them, making them very 

 noticeable, and by their location, nearly all being on the trunk and 

 large limbs. Destruction of the egg masses should be in July as 

 soon as they appear, and again at any time between the first of 

 October and the last of April, and spraying should only be necessary 

 if the destruction of the eggs has been neglected. Trees not in- 

 fested can be kept clear, provided their branches do not touch those 

 of infested ones, by banding the trunks with Tree Tanglefoot, for as 

 the female moths cannot fly, such trees can only be reached by the 

 moths or caterpillars crawling to them. 



