372 



REPORT OF THE COMMISSIONERS OF 



form of a scraper, the task is easily and quickly performed. Dr. Howard has recom- 

 mended 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 prevent 

 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 egg 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 



"Figure 2. — Dibrachys BOUCHEANUS: a, larva ; !>, pupa; c, adult female— greatly enlarged; d, head of larva; 

 e, antenna of adult — still more enlarged. Lines beside figures represent natural size. (After Howard : U. S. 

 Department Agriculture, Division Entomology. Tech. ser. No. 5, 1897). 



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 until 

 autumn, or, better still, until early spring, since there will 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 collect in midsummer the eggs laid by the first brood of moths. 

 In case it is impracticable to collect the eggs, dependence must be placed upon 

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

 the season under favorable conditions. In many instances there will be more or less 



