22 



of shade trees. It should be noticed here that an abstract of the 

 following pages, with some of the illustrations, has already 

 appeared in the I'ecently published Third Report of the State 

 Agricultural Experiment Station, and the illustrations used in 

 the former paper have been loaned by the Station for use in 

 this. No one should regard these papers, although the subject 

 is similar, as duplicates, for not only is the subject treated some- 

 what differently in each, but this paper is far more complete 

 than the space which could be given in the Station Report 

 permitted. It has been thought that, as full and complete an 

 account as may be of all the insects known to infest the elm 

 would be useful for reference as well as for the present. Of course, 

 in a paper like this very much is necessarily included for the sake 

 of completeness which is not unknown or unfamiliar, to entomolo- 

 gists at any rate, but not a single species of this sort is mentioned, 

 I believe, which has not been mentioned in letters received from 

 different parts of the .State and information respecting it de- 

 sired. So far as the general subject is concerned, it would seem 

 to the writer that no apology or excuse ought to be needed for in- 

 vestigating the enemies of so noble a tree as the elm, and, while 

 some of the species herein enumerated are at present of compara- 

 tively little importance, it is yet more important that they should 

 be at least brieffy considered than it may at first thought seem to be, 

 because no exjoerience is more common than that a species of in- 

 sect hitherto inconspicuous, both as to number and damage done 

 by its ravages, suddenly becomes very conspicuous by its rapid 

 and unaccountable increase. No species of insect is to be passed 

 over as of no possible interest, although we may well devote much 

 greater attention to some than to othei-s. From this, it follows 

 that all observations of formers, fruit growers and all otiiers are of 

 value, and the great advantage which must result from co-opera- 

 tion in the study of insects is manifest. The very great unlikeness 

 which is found to exist between the young and the adult of most 

 insects, renders the study of their life history the more puzzling 

 and gives additional value to every observation. How great the 

 changes through wliich an insect may pass during its cycle of ex- 

 istence may be will appear by and by, as we study the Aphides in 

 the last part of this paper. But let us return to the elm. As has 

 been said, no excuse ought to be necessary to justify devo.ting time 

 and space to the insects that are destroying, or may do so, this 

 tree. It is always easy to understand how any damage to farm 



