EXTENT OF INSECT DEPREDATIONS. 3 



No asylum is SO secure that they may not intrude; no condiLiou in 

 life is exempt from their presence and attack. 



From this general diffusion there necessarily results extensive losses. 

 Provided often with wonderful means for self-preservation and for the 

 perpetuation of the species, they are ever ready in the exercise of their 

 powers to dispute with man his claim of exclusive right in property. 

 Never without the imposition of a heavy tax upon the products of his 

 labor, they often manifest a determination to wrest from him the en- 

 tiro results of a season's toil. Many of the more injurious species liv- 

 ing solely upon such vegetable productions as man regards as esseatial 

 to his welfare and almost indispensable to his existence, there follows 

 as the consequence of the "struggle for life," continual collision and 

 antagonism. Have the study and labor of a long series of years at 

 length brought the products of his garden and his orchard to such a 

 degree of perfection that only traditionary lore can trace therein spe- 

 cific identity with the wild, uncultivated parent-jDlant, it would seem, 

 at times, as if all this improvement served no other end than to pro- 

 vide more sumptuous repasts to augmented hordes of insects with 

 greatly increased powers of destructiveness. 



To the vegetable world, insects are mainly indebted for their suste- 

 nance, and a vegetable growth entirely free from insect attaclc \yould 

 be an anomaly in nature. From careful and extended observations, it 

 has l)een estimated that there are, upon an average, six species of in- 

 sects attacking each species of plant. Upon most of our cultivated 

 filants, such as garden vegetables, shrubs, trees, grasses, cereals, etc., 

 they have become quite numerous, for the qualities resulting from 

 careful culture whicli have made them more valuable tons, have, at the 

 same time, rendered them more attractive to insects. Ten vears ago 

 (since which time great progress has been made in economic entomol- 

 ogy), Dr. Packard stated* : " I could enumerate upwards of fifty 

 species of insects which prey upon cereals and grasses, and as many 

 which infest our field crops. Some thirty well-known species ravage 

 our garden vegetables. There are nearly fifty species which attack the 

 grape-vine, and their number is rapidly increasing. About seventy- 

 five species make their annual onset upon the apple-tree, and nearly as 

 many may be found upon the plum, pear, peach, and cherry. Among 

 our shade trees, over fifty species infest the oak ; twenty-five the elm ; 

 seventy-five the walnut, and over one hundred species prey upon the 

 pine." 



The above stated numbers have already been found to be much be- 

 low the truth. Several, if not all of them, may be safely doubled, for 



* First Ann. Rep. Ins. Mass., 1871, p. 5. 



