THE MOUNT DESEET REGION 13 



largely instrumental in keeping these prolific and destructive 

 insects within bounds. 



Another factor of importance relative to a careful survey 

 of the insect fauna of a region is the having on record the 

 species to be found there at a certain time, so that, in the 

 future, changes which we know are slowly but certainly affect- 

 ing insect life can be tabulated and the causes which have 

 brought about an increase or diminution of certain species 

 may be better understood. The many introduced trees and 

 plants have been and may continue to be a factor toward 

 further insect distribution. Already there have occurred 

 among plants of economic importance such insects as the 

 Colorado potato beetle, the lunate onion fly and the narcissus 

 fly on bulbs, the European cabbage butterfly, etc. The bro\vn- 

 tail moth, abundant from 1909-1915, when Bar Harbor spent 

 over $2500.00 in keeping it in check, has now apparently dis- 

 appeared, at least I have seen but one moth (July 16, 1923) 

 since starting my work in 1918. The gypsy moth is reported 

 on the island, although not yet abundant. The danger from 

 introduced species cannot be overestimated, and prompt 

 action should be taken to destroy them, otherwise — 



"A big invading army 



Tliey make the earth their own. ' ' 



Introduced without their parasites and other natural enemies, 

 the only immediate recourse is in spraying with arsenical 

 preparations, with the result that many of our native species 

 disappear, the balance of nature is disturbed and the diver- 

 sity and beauty of our insect fauna are gone. The rich insect 

 fauna of Mount Desert shows that we are still dealing in 

 places with an almost undisturbed ecological condition, which 

 we trust may continue to survive in the many sequestered 

 parts of the island. 



Prior to the work of preparing this list there had been 

 practically no special entomological work done on the island. 

 A number of butterflies obtained by various collectors visit- 

 ing Mount Desert are mentioned in Scudder's great work.^ 



""Butterflies of eastern United States and Canada," by Samuel H. Scudder, 

 3 volumes, 1959 pages, and 89 plates, 1889. 



