I30 AGRICULTURAL EXPERIMENT STATION. 



Criidc petroleum, light and heavy, has been used as a sub- 

 stitute for kerosene, but neither is as satisfactory. The heavy 

 oils form globules that hang together and tend to unite in a 

 mass rather than to spread out in a film. The lighter oil spreads 

 better at first, but as the gasoline and other volatile parts evapo- 

 rate, the vaseline and other heavy products tend tO' draw to- 

 gether. 



A sohtblc crude oil has been prepared by a Baltimore firm and 

 sent me for trial. LJsed in the laboratory it mixed readily with 

 water and killed promptly all the larvae and pup^ in the trial 

 bottles. While it cknided the water a little, it did not turn it 

 milky and the action was a little slower than that of the Phinotas 

 oil. 



August 26th, I sent out two of the boys with instructions to^ 

 spray the lot pools in New Brunswick from which our experi- 

 mental material was usually derived. An atomizer was used and 

 a very small amount of the material was needed : the instructions 

 were to simply cover the surface and tO' see what would happen. 

 The report was as follows : "The spray looked about like w^ater 

 and it gave the pools a clouded appearance. The larvae and pup:e 

 became active and uneasy as soon as the surface was covered. 

 Half an hour after the spraying a great many of the pupae were 

 dead; but most of the larvae were still active, although they did 

 not act naturally. The petroleum also^ affected the other insects : 

 numerous dead beetles and w'ater boatmen were noticed, and 

 cjuite a few climbed out at the sides and on the stones to escape. 



"August 27th, examined the pools which were sprayed yester- 

 day and found that the water has the same cloudy, dirty appear- 

 ance and as if there was a scum of grease on the surface. The 

 larvae and pupae were all dead, except one pupa in one of the 

 smaller pools and one larva in the largest pool. The pupa was 

 nearly dead, but the larva was quite lively. 



"Quite a number of dead adult Chirononiids as well as Culex 

 pipiens and one C. jamaicensis w^ere noted on the surface.'' 



September 2d I sent one of the boys out for further observa- 

 tion, and he reported half the pools entirely dry, others with only 

 an inch or less of water and one with six inches of water, with 

 numerous tgg boats and a large number of recently liatched 

 larvae. 



This observation is important because in five days after an 

 application which killed ofi^ nearly all insect and all mosc|uito 

 life, the area was again infested, though there had been prac- 

 tically no addition bv rains and there had been, indeed, an actual 

 shrinkage in the size of the pool. 



