8 BULLETIN 204, U. S. DEPARTMENT OF AGRICULTURE. 



used at the laboratory are of original design and have been constructed 

 for the purpose of furthering the gipsy-moth investigations. Much 

 valuable information of a biological nature has been secured which 

 is not only of direct value to the- parasite phase of the gipsy-moth 

 work but has been found useful in connection with insect problems 

 in various parts of the country. 



RECENT COLONIZATIONS AND RECOVERY OP IMPORTED PARASITES. 



During the past two or three years careful investigations have 

 been carried on to determine the increase and spread of the different 

 parasites. In the summer of 1914 this work was in charge of Mr. 

 S. S. Grossman. As large a number as possible of the different 

 species have been liberated in the remote parts of the infested area 

 for the purpose of securing the establishment of these valuable 

 species over the entire territory at the earliest possible date. In 

 the fall of 1913 Anastatus Hfasciatus was recovered from 41 towns 

 and the parasitism in the collections secured averaged about 30 

 per cent. ,From one collection over 43 per cent of the eggs had been 

 destroyed by this insect. As a result of the collection made during 

 the winter, 1,561 colonies of this species, totaling 1,561,000 speci- 

 mens, were liberated; 1,047 of the colonies were placed in 12 towns 

 in Massachusetts and 514 in three towns in New Hampshire. This 

 insect spreads very slowly, hence it is necessary to liberate many 

 colonies. The plan which is being used is to place a sufficient num- 

 ber of colonies in a town so that no further colonization in that town 

 will be necessary. The work on this insect required the collection 

 in the fall of 1913 of .about 7,500 gipsy-moth egg clusters and these 

 were secured from over 100 selected localities. 



In the fall of 1913, 33 towns were colonized with Schedius leuvanae. 

 The number of colonies placed in a town varied from 1 to 10, depend- 

 ing on the gipsy-moth infestations. Most of the colonies were liber- 

 ated in the southern part of the infested territory in Massachusetts, 

 as it was believed that this section would be favorable for the survival 

 of the species during the winter. In all 110 colonies were liberated, 

 containing over 375,000 individuals. This species spreads more 

 rapidly than Anastatus, so it is not necessary to place as many 

 colonies in a given area. Over 14,000 gipsy-moth egg clusters were 

 collected from about 100 selected localities within the area bounded 

 by Exeter, N. H., and Berlin, Bolton, and Mashpee, Mass. This 

 material was used at the laboratory to secure records of the percentage 

 of parasitism in colonies that had been liberated in previous years. 



The spring of 1913 was very favorable for Apanteles ladeicolor, and 

 it was recovered from 69 towns. This was the result of collections 

 of 92,000 brown-tail moth webs, a supply coming from every one of 



