42 prfsident's address. 



study of the chemical combination of the materials used for 

 particular sprays, for the different groups of insects, we 

 have made them more effective as contact or stomach poisons. 

 For example, in arsenical poisons, Paris Green was first used 

 to destroy codling moth ; it was found that arsenite of soda 

 was, in many cases, a cheaper and better spray than Paris 

 Green; now, in arsenate of lead, we have a much more per- 

 fect and longer lasting spray than both our former chemicals, 

 fumigation with hydrocyanic acid gas is another very effi- 

 cient agent in destroying many injurious insects, that suck 

 up the sap, and stick to the bark and foliage. In one appli- 

 cation, every scale and aphis on a citrus tree can be de- 

 stroyed ; whereas the difficulty in the spraying of all ever- 

 green trees is to wet all parts, and also the trees frequently 

 require several such applications. 



Fumigation is also being largely adopted in the destruction 

 of household pests, such as bugs, cockroaches, etc., the pene- 

 trating power of this volatile gas finding its way into the 

 most minute cracks or crevices, and in about four hours will 

 kill all these insects in every stage of development. It is 

 also being used in the same way in ships for fumigating the 

 cabins ; and the flour-millers are finding it very effective in 

 destroying the Mediterranean-flour-moth. 



The entomologist has many important problems to deal 

 with at the present time in the study of insect-pests ; but 

 experience has taught him that when it has been carefully 

 studied, there is not one that cannot be checked and reduced, 

 until it becomes of no commercial importance. He has 

 reached the proud position, that he is consulted by all sorts 

 and conditions of men ; the orchardist from the Hawkesbury 

 River flats, the squatter from "beyond the rainless Barwon," 

 the sugar-planter from the tropical scrubs, the coconut and 

 rubber-planter in the Pacific Islands, the farmer from the 

 Riverina, all come to him. In the city, the merchant, the 

 doctor, the seedsman, the architect, and housewife seek his 



