56 



N. S. ENTOMOLOGICAL SOCIETY. 



TABLE No. I. 



NUMBER OF BROWN TAIL MOTH NESTS FORMED FROM 3 EGG MASSES 



PLACED ON TREES SPRAYED WITH THE FOLLOWING POISONS 



ALONE AND IN COMBINATION WITH FUNGICIDES. 



Spray applied July 7th and 8th. 

 Feeding commenced August 10,th. 



Where the poisons were used with Bordeaux mixture the least killing took place, 

 sixteen nests being formed out of a possible thirty. With the other fungicides, and 

 with the poison alone, no great difference appeared in this test, any superior killing 

 power of the poison alone and with sodium sulphide (soluble sulphur) being practically 

 offset by the superior adhesiveness of barium tetrasulphide and lime. The action of 

 triplumbic lead in combination with Bordeaux mixture and of home made arsenate of 

 lead should be kept in mind, as they will be referred to later in connection with another 

 experiment. 



The results from this experiment showed that a large proportion of the browntail 

 caterpillars were, as we suspected, killed late in the season by the poison of the last sum- 

 mer spray adhering to the leaves for a sufficiently long period to affect the fall-feeding 

 larvae. 



During the winter of 1915-16 the writers made a comparison of the results of their 

 experiments with those of other workers obtained elsewhere. The result was to bring 

 to light a mass of very conflicting data regarding this question. The need for further 

 work along certain definite lines being very evident, it was decided to test the effect of 

 all the common poisons, both by themselves and in combination with fungicides, against 

 several common species of insects. In this way we hoped to get such a mass of data that 

 accurate averages might be obtained, showing the killing power of each combination in 

 comparison with others, free from such errors as would be likely to occur in feeding 



