INSECTS AFFECTING PARK AND WOODLAND TREES I4I 



masses, and most excellent results were obtained. In places where this is 

 practicalh" the onl\- shade tree pest, this system or the payment of a bounty 

 on the egg masses would undoubtedly result in the pest being kept under 

 control at a comparatively small outlay. As the eggs are in a compact 

 mass which is reaiiily torn from the sujjporting cocoon, either b\' hand or 

 some f6rm of a scraper, the task is easily and quickl)' performed. Dr 

 Howard has recommended the use of creosote oil for the destruction of the 

 eggs, since each mass has only to be moistened with the substance. In 

 winter it is necessary to add some turpentine in order to keep the creosote 

 liquid. On account of the female being wingless, a tree once thoroughly 

 cleaned will not become reinfested very soon if larvae are not abundant 

 near by, and even then a band of loose cotton bound tightly near its middle 

 around the trunk and the portion above the string turned down, will pre- 

 vent their ascending and a consequent reinfestation. It should be kept in 

 mind that only the eggs must be collected or destroyed, on account of the 

 beneficial parasites which may occur in cocoons not bearing e^^i^ masses. 

 This is specially true in the autumn and applies to a certain extent in the 

 spring, since it has been shown that some parasites hibernate as larvae 

 within the cocoons of the host, and if these are collected and destroyed, it 

 means the death of many beneficial forms. The egg masses are more 

 readily seen after the leaves have fallen and in localities like Albany, where 

 one annual generation is the rule, the gathering of the eggs may well be 

 deferred till autumn, or, better still, till early spring, since there Vv'ill then 

 be less chance of destroying valuable parasites. As the young caterpillars 

 begin to hatch the latter part of May, collection of the egg masses can not 

 be delayed with safety after the middle of that month. In Boston, New 

 York city and more southern localities, it may be necessary to make a mid- 

 summer collection of the eggs laid by the first brood of moths, and in case 

 it is impracticable to do this, dependence must be placed on spraying w'ith 

 some arsenical poison. This is satisfactory if properly done early in the 

 season under favorable conditions. It is very difficult to have the spray- 

 ing properly done, and then there may be hindrances incident to sevei"al 



