384 W. F. FISKE. 



discovery and proper application of the remedies for the depredations of the former, 

 and will tend to remove the repugnance wherewith the latter are commonly regarded. 



" Destructive insects . . . are exposed to many accidents through the influence 

 of the elements, and they fall a prey to numerous animals, many of them also of the 

 insect race, which . . . contribute to prevent the imdue increase of the noxious 

 tribes. Civilization and cultivation, in many cases, have destroyed the balance 

 origmally existing between plants and insects and between the latter and other 

 animals. . . , The destruction of insect-eating animals, whether quadrupeds, birds 

 or reptiles,- has doubtless tended greatly to the increase of insects. Colonization and 

 commerce have to some extent introduced foreign insects into countries where they 

 were before unknown. It is to such causes as these that we are to attribute the un- 

 welcome appearance and the undue multiplication of many insects in our cultivated 

 groimds, and even in our store-houses and dwellings. . . . 



" To understand the relation that insects bear to each other and to other objects, 

 and to learn how best to check the ravages of the noxious tribes, we must make our- 

 selves thoroughly acquainted with the natural history of these animals. This subject 

 is particularly important to all persons who are engaged in agricultural pursuits. 

 For their use, chiefly, this account of the principal insects that are injurious to vege- 

 tation in New England has been prepared." 



I venture to assume that this statement of the case would be approved by the 

 majority of the economic entomologists of to-day. The same arguments have been 

 put forward many times to emphasize the desirability or need of establishments for 

 research into the natural histories of the " noxious tribes " of insects, and the lines 

 suggested by Dr. Harris have been followed assiduously. 



But although we have accepted the arguments and conclusions adduced by Dr. 

 Harris, and have modelled our system for the acquisition and application of knowledge 

 accordingly, our conception of the relations which species bear to each other and to 

 other objects is fundamentally different from his. His arguments, conclusions and 

 recommendations were based upon the pre-Darwinian or Mosaic conception of the 

 origin of species, and any theory or hypothesis which might be formulated concerning 

 the character of their relations to each other and to their physical enviromnent was 

 necessarily in accord with what now appears to us an archaic and impossible point 

 of view. This is sufficiently indicated by the following further quotation from the 

 introductory paragraphs to Dr. Harris' report, (The italics are mine.) : — 



" Destructive insects have their appointed tasks and are limited in the performance 

 of them ; they are exposed to many accidents through the influence of the elements, 

 and they fall a prey to numerous animals, many of them also of the insect race, which 

 while they fulfil their oivn part in the economy of nature, contribute to prevent the 

 undue increase of the noxious tribes. Too often by an unwise interference with the 

 plans of Providence we defeat the very measures contrived for our protection. We 

 not onlv suffer frpm our own carelessness, but through ignorance fall into manv mis- 

 takes. . . . Deprived of their natural food by the removal of the forest trees and 

 shrubs that once covered the soil, insects have noiv no other resource than the 

 eultivaied plants that have taken the place of the original vegetation. . . . We 

 have no reason to believe that any absolutely new insects are created or generated 



