404 



ECONOMIC ENTOMOLOGY 



every ten, or 90 per cent, must be parasitized. To rely entirely upon 

 egg parasites, such as Anastatus or Schedius, to destroy such a large 

 percentage of the eggs was out of the question, for these parasitized 

 only the upper layer of eggs in each mass. It became necessary, 

 therefore, to call in the aid of the parasites affecting the caterpillar and 

 the pupa. Consequently efforts have been made to secure a sequence 

 of parasites from foreign countries so that every stage of the moth is 

 subjected to attack, and which would bring up the death-rate to 85 or 

 90 per cent. (See Bull. 91, U. S. Bureau of Ent.) 







Fig. 255. — Apanleles lacleicolor: adult female and cocoon. Mvich enlarged. {After 



Howard and Fiske.) 



The task of importing the foreign parasites of the Gypsy and the 

 Brown-tail Moths to the United States has been a most arduous and 

 difficult one. In the first place it has involved much labor in getting 

 competent collectors in Europe to gather sufficient parasitized material, 

 for the plan of the utilization of foreign parasites on a large scale in the 

 control of injurious forms is recent in conception, and was put into 

 operation for the first time by the U. S. Bureau of Entomology in the 

 fight against the Gypsy and the Brown-tail Moths. In the second 

 place, many difficulties in transportation have had to be overcome. 

 In the third place, the work of sorting out the various parasites and 

 herding them in sufficiently large numbers in the laboratories for 



