Many Federal, State, and municipal officials also cooperated by 

 sending in miscellaneous collections. Since 1935, when the labon^tory 

 was moved to New Haven, Conn., the number of field collections 

 of native larvae has been greatly reduced. 



The bulk of the material handled in these studies consisted of 

 larvae and a few pupae of macrolepidoptera, microlepidoptera, 

 Tenthredinoidea, and a few Coleoptera. Numerous hosts and their 

 parasites were reared, and considerable knowledge was acquired 

 about their life histories, habits, and abundance. 



In the early years of these studies numerous parasites were reared 

 that were difficult to determine specifically until revisions had been 

 made on many of the groups. Many parasitic species, new to science, 

 were reared from the field collections; and as a result most of those 

 reared from the macrolepidoptera and many from the microlepidoptera 

 have been described and named by taxonomists. From the micro- 

 lepidoptera, however, a considerable number of the parasites reared, 

 and determined as new, have not been described and given species 

 names because the series of adults obtained were too few in number, 

 or the adults were all of one sex. In other series, because of the need 

 for revision, certain groups cannot be determined beyond the genus. 



Considerable time has elapsed since much of the field work for 

 this study was done. This time lapse has permitted taxonomists to 

 become more familiar with the particular insect groups, thus facilitat- 

 ing determination of many of the species. 



Field Data Requested From the Collectors 



Insect collections were mailed to the laboratory in mailing tubes 

 and each collection was accompanied by a note slip. Each collector 

 was requested to furnish the following information: (1) Date of 

 collection; (2) name of collector; (3) town and State where collection 

 was made; (4) host plant; (5) estimate of insect's abundance; (6) 

 degree of defoliation, if any; (7) approximate area of infestation; and 

 (8) additional information of interest. 



Methods of Handling Field Collections 



Inasmuch as most of the insects received were still in the larval or 

 pupal stage, it was necessary to place them in rearing to permit 

 issuance of adults or parasites. Because of the differences in habits 

 of the various species received, and because of the lack of knowledge 

 concerning the hibernation requirements of many of them, it was 

 also necessary to use several types of cages. Undoubtedly some 

 species failed to reach maturity because of faulty handling or improper 

 hibernation facilities. 



On arrival at the laboratory each collection was examined. The 

 specimens were counted whenever possible and placed in rearing 

 cages. Usually no attempt was made to count such insects as leaf 

 miners and bud and twig borers in the larval stage. Sometimes an 

 estimate was made of the number in a collection; at other times 

 adults, parasites, and dead larvae were counted when the experiment 

 was closed. 



Attempts were always made to identify the insect in the larval stage 

 when such specimens were received. This was especially so when a 



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