﻿4 BULIaETm 1363, U. S. DEPAETMENT OP AGEICULTUKE 



The territory from which the collections were received is repre- 

 sentative of the gipsy-moth area of New England, the bulk of the 

 material, however, being from those sections about Melrose High- 

 lands, Mass. ; Bangor, Me. ; Claremont, N. H, ; Westerly, R. I., and 

 Putnam, Conn. 



There are also collections (not included in the above summary) 

 from the gipsy-moth territory in New Jersey. In this area there 

 had been prior to 1921 no systematic introduction of parasites and 

 the material obtained answers well for check purposes. These 

 collections are represented by over 125 species aggregating at least 

 10,000 larvae. 



CARE OF COLLECTIONS AND METHODS OF REARING 



Ordinary mailing tubes, 2 inches in diameter and T inches long, 

 with screw tops, are used with great success for the shipment of 

 material from the field. On receipt of the collections at the labora- 

 tory the contents are sorted, identified if possible, and placed in 

 receptacles for rearing. 



Various methods are used in handling the collections. In the case 

 of known insects the task is easy since many species can be success- 

 fully reared in pasteboard boxes or in covered trays. The frame- 

 work of these trays is of wood, measuring 12 by 12 by 5 inches ; the 

 bottom is covered with cloth and can readily be replaced when 

 necessary. All trays are furnished with tightly fitting glass covers 

 which slip into a grooved top. Where there is any doubt as to how 

 the species may best be reared, glass jars, supplied with earth, are 

 used. 



Hibernating larvae and species which pass the winter as pupae or 

 prepupae are difficult to handle successfully. In caring for the hi- 

 bernating larvae the best results were obtained from the use of Riley 

 cages. For pupal hibernation, glass jars, galvanized-iron cylinders 

 with bottoms of fine mesh wire screening, and wooden boxes of 

 various sizes are used. These are partially filled with earth and the 

 larvae allowed to transform at will. The glass jars are either re- 

 tained in the outside rearing cage or brought into the cellar of the 

 laboratory, where they are not subject to extreme temperatures. 

 The cylinders and boxes which have been successfully used are set 

 in the earth as soon as the larvae pupate, and covered with straw. 

 Practically the same methods are used in caring for the tachinid and 

 hymenopterous parasites. 



LIFE HISTORY AND HIBERNATING HOSTS 



Briefly, the life history of Compsilura concirmata is as follows: 

 During the spring the last-stage larvae issue from their hibernating 

 hosts and pupate close by. Ten days or so later the adults appear. 

 In New England there are two or more generations upon alternate 

 hosts, the progeny of the last generation hibernating as larvae within 

 certain lepidopterous pupae. Spring emergence of the overwintering 

 generation is variable, depending upon climatic conditions (Table 

 2). During 1921 a few flies issued in April, whereas the material 

 collected in 1916 gave no results in 1917 until June 11 and later. 

 Most of the rearing records, however, which have been conducted 



