1(U ANNUAL REPORT 



it not agreeing, as they all died in the course of a few days. Other 

 species feeding on the leaves of the same branch were thriving 

 exceedingly. A few of these confined specimens began to bring 

 forth young aphids of the third generation, which showed even 

 more activity than either of the two previous generations, wander- 

 ing about very restlessly without even attempting to feed; they all 

 perished in a short time. The food plant of the second generation 

 after acquiring wings and of their immediate issue, is, therefore, 

 not the poplar but some other plant. The active habits, long beak 

 and other characteristics of the third generation would indicate 

 that they feed on harder parts of a plant, as the bark or twigs, not 

 excluding the roots, 



A short summary of the life-history would, therefore, give us 

 the following stages : 



1. Egg hatches about the middle of May. 



2. The stem-mother starts the gall in which she passes through 

 four months in the course of about two weeks; begins to bring 

 forth the second generation about the first of June, and continues 

 through the month, after which she dies without leaving the gall. 



3. The second generation also passes through the customary 

 months in the gall; all acquire wings and leave the gall about the 

 middle of July, when they migrate to some other plant, yet 

 unknown. 



4. The following generations are now continued under different 

 conditions, until in fall, when the true sexes are produced, which 

 couple, and the females return to the poplars to deposit the fecun- 

 dated eggs. 



In places where this species should become so numerous as to 

 need some check, the best remedy would evidently be to pluck the 

 galls and destroy them during the month of June, before the sec- 

 ond generation has taken to flight. The galls are almost all con- 

 fined to young trees of six to fifteen feet in height, so there is no 

 great difficulty in reaching them. Picking the galls after the mid- 

 dle of July is, of course, of no use, unless to remove them as 

 unsightly objects. 



President Elliot. We have another paper in this direction by 



Prof. Lugger. 



INSECTS INJURIOUS TO SMALL FRUIT. 



By Prof. Otto Lugger, Ph. D. 



Ladies and Gentlemen: 



Before entering into a discussion about some insects injurious 

 to currants, blackberries and raspberries, which are, perhaps, all 

 well known to you, permit me to make some general remarks as to 

 how noxious insects multiply, and the methods employed by nature 

 to check any undue increase. 



We all know that all insects undergo a number of metamor- 

 phoses before reaching the age of sexual maturity. These meta- 

 morphoses are more or less abrupt, though the differences between 



