88 THE EEPOKT OF THE Ko. 36 



into the matter and succeeded in finding the insect responsible, but was not able to 

 get it determined. If my memory serves me rightly, it was neither pmtensis nor 

 invitus. One of its favorable food plants is the mullein. 



Prof. Caesar : There are a number of interesting points of comparison 

 "between Lygus invitus and Neurocolpus nubilus; (1) The damage done by the 

 latter is not nearly so great as that done by the former as described by Prdf. 

 Brittain, and there is none of that corky growth or rough brown surface mentioned 

 by him. (3) Neurocolpus nubilus seems, unlike the other species, to have no 

 instinct to cause it, if it drops to the ground, to find its way back to the trunk, but 

 instead wanders aimlessly around. Neurocolpus nuhilus will feed on a great 

 number of plants. It is probable its native host plant is sumac. 



It is strange that while Lygus invitus is to be found all over Ontario in just 

 as great abundance apparently as the other species, it does not, so far as I can see, 

 do any harm to apple.s or pears. As for the dilBculty of seeing the insects laying 

 eggs, both species must be much alike for we could never find Neurocolpus nubilus 

 ovipositing or even copulating. 



Mr. Petch : This year we had a frost in the blossoming period, and I think 

 the injury was caused by frost to the blossoms. However, as the injury occurred 

 on only one tree I cannot see how that can be the cause, and I do not know what 

 the injury to blossoms by this insect is like. Does it give the appearance of having 

 been frozen? 



Prof. Brittaix : Yes, it looks very much like fire blight. The blossoms are 

 brown and dead and I attribute a great deal of the so-called frost trouble lo 

 Lygus invitus. 



Mr. Petch : AVith the use of Black-Leaf -40 in the ordinary strength do you 

 find it injurious to the foliage of apples ? 



Prof. Caesar : We found that where Black-Leaf -40 was put on very heavy 

 along with lime surphur it did seem to injure the apple foliage to some extent. 



Mr. Tothill: The two accounts we have had of Lygus invitus in Ontario 

 and j^ova Scotia suggest the possibility that there may be two species concerned. 

 The species of American Capsidw are, of course, based on a study of museum 

 specimens only. They are not based on habits and as the group is an extremely 

 difficult one to do anything with, and as no breeding work of any kind has been 

 done, it seems to me from the great differences in the habits of the so-called species 

 that it is just possible there are two species concerned. 



Prof. Brittain : Mr. H. H. Knight writes me that he is convinced that the 

 species in Nova Scotia is a new variety, lie intended to describe it as such in the 

 near future. 



Mr. Tothill : That would seem to bear out this contention. 



The President : If there is no further discussion on these two papers we will 

 proceed to the next, which is a paper by Dr. Cosens entitled, " The Founding of the 

 Science of Cecidology." 



THE FOUNDING OF THE SCIENCE OF CECIDOLOGY. 

 A. Cosens, Toronto. 



At a time when the problem of gall formation is exciting deep and increasing 

 interest, it seems opportune to consider for a few minutes those investigators, who, 

 lured by the fascination of the subject, laid the foundation for its scientific 

 treatment. 



