328 Professor E. B. Poiilton on 



Mr. G. A. K. Marshall joined in the work, and after a time 

 convinced me that it would be better to defer the records 

 of predaceous Hymenoptera to a second part. So much 

 has been done that the paper would appear to be a com- 

 plete abstract of literature bearing on the subject ; and if it 

 failed to be truly complete great harm would be done; for 

 the way to an adequate statement would certainly be barred 

 for many years to come. It was therefore determined to 

 put off the appearance of Part II, devoted to the predaceous 

 Hymenoptera, until the abstract of published records is as 

 full and complete as it can be made. It is believed that the 

 work will be finished early in 1907, and that no long interval 

 need elapse between the two sections of the memoir. 



The same argument does not apply to the First Part, 

 which is in the main a presentation of new records, and 

 does not profess to contain anything like a complete 

 abstract of the published records scattered chiefly in the 

 form of brief notes, though a voluminous literature. At 

 the same time any published statements which have come 

 to light are included ; and many more will certainly be 

 found in the systematic search for records of predaceous 

 Hymenoptera. Any such additions to Part I will appear 

 in the form of an Appendix at the end of Part II. 



I desire to thank the Council for their courtesy in 

 permitting, as an exceptional privilege, the inclusion of 

 predaceous insects and their prey captured after the date at 

 which the paper was read, — June 6th, 1906. All such addi- 

 tions will be immediately recognized by their dates. Owing 

 to this concession many of the conclusions rest upon a far 

 broader foundation than would otherwise have been possible. 

 It is hoped that this paper will be of some use to those 

 who are interested in the problems of Economic Entomology 

 rather than in the study of Insect natural history or bio- 

 nomics for their own sake. With this object the popular 

 names have been used whenever possible, and the classifica- 

 tory position of the prey indicated. I have been much im- 

 pressed with the imperative necessity for the accumulation 

 on a very large scale of this kind of evidence, if trustworthy 

 conclusions are to be reached — conclusions safe enough to 

 become the justification for practical measures. It is not 

 sufiicient to know that an insect is predaceous, and that it 

 is believed in a general way to attack particular species or 

 groups of species. We need precise records and the care- 

 i'ul preservation of material for critical examination in the 

 future. Thus it will be found in numbers of cases that 



