a" > 
41 
Mr. Woodworth mentioned that he had observed in Arkansas three epidemics 
amongst insects which were so severe as apparently to exterminate the infested 
species: one of these was the tomato worm. 
Mr. Fletcher asked whether Phytonomus nigrirostris had been observed as 
injurious to clover. He had frequently found the larvee feeding on the heads of 
clover as well as the characteristic cocoons. He had found it in many parts of 
Canada, but upon one occasion, as recorded in his report for 1884, it was 
injuriously abundant at Dalhousie in New Brunswick. Mr. Gillette also spoke on 
insects injurious to clover. 
Prof. Smith gave an account of some experiments with preservative fluids. 
He had found a mixture of equal parts of acetic acid and alcohol very satisfactory 
both in regard to preserving form and colour of delicate insects. 
The subject was earnestly discussed by all present as being a subject of much 
importance. Mr. Woodworth gave as a method which he had found satisfactory 
for larve, to kill in water heated to 90° centigrade: leave from 1 to 5 minutes ; 
then put in alcohol 35° 1 to 2 hours, 50° from 6 to 8 hours, 75° for 24 hours or 
more and then to absolute aleohol. This would usually preserve perfectly and 
was a recognized process for hardening and preserving for histological purposes. 
Mr. Fletcher asked whether in the case of large larve it was necessary to 
puncture the epidermis so as to allow the preservative fluid to penetrate. 
Mr. Woodworth answered that this was not often necessary. 
Mr. Fletcher spoke of a large series of the larvae of Sphinw chersis which he 
had taken during the past summer upon various species of Fraxinus. They varied 
so remarkably in colour that he was able to separate about 40 which showed 
different markings from the usual glaucous green to a rich vinous purple with 
yellow epidermal dots. He had placed them iu a jar of 35° aleohol and had 
‘found that those at the top were very much discoloured and that those lower 
down were less so, those at the bottom being of good colour. On placing some 
in stronger alcohol the discoloration was intensified. He thought the discolora- 
tion was due to the gradual decay of the central portions of large larvee, but could 
not understand why those at the bottom were less discoloured than thdse at the 
top of the jar. 
Prof. Forbes stated that he used the method described by Mr. Woodworth in 
his laboratory and found it fairly successful. It does not preserve greens well, 
but browns are preserved and the markings are well shown. 
Mr. John Marten said that hot alcohol was a convenient way of preserving 
specimens by this method and that it answered equally well as killing in hot water. 
Prof. Forbes read a “Summary history of the corn plant louse.” This was 
an intensely interesting paper and gave the results of continued observations for 
some years by Prof. Forbes and his assistants. It gave the life-history both 
above and below the ground. The relations existing between the aphis and the 
ants which were always found in company with it were explained and suggestions 
for remedies based on these observations were made. 
The discussion on the paper was postponed until the next session. 
At the afternoon session 18 persons were present. The president called for 
discussioa of Prof. Forbes’s paper. Messrs. Howard, Riley, Fletcher and Forbes 
discussed the points brought forward and the difficulties of getting at accurate 
and final results were brought out. The question of possible relationship between 
the apple plant louse and the corn plant louse was discussed by Messrs. Riley 
and Forbes. 
