]^(5 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



are made. Of course a variation in the warmth of the liquid would 

 caule a difference. Further experiments, bringing in the tempera- 

 ture factor, are planned for next summer. The experiments cited 

 herewith were performed late in the fall, and the steam caused by 

 the union of the acid and water did not cease until the liquid was 

 fairly cool. 



In connection with these experiments the question arose, " Is it not 

 possible that fumes which would be fatal, if breathed, rise from the 

 jar before they are visible?'" This was answered in the negative by 

 placing a live guinea pig in a wire cage about G inches above the top 

 of the jar immediately after the charge of cyanide had been lowered 

 into the acid. Visible fumes began to rise two minutes after plac- 

 ing the charge, and a few seconds later the guinea pig succumbed, 

 showing that the dangerous gas was not given off in a fatal amount 

 until fumes were observed. It would seem, then, from these results, 

 that, on a very conservative estimate, one can depend upon at least 

 twenty seconds when double sacks are used, and much can be done 

 in that time. 



Another important question connected with the use of hydrocyanic 

 acid gas is the distance it Avill penetrate into a semisolid mass — a 

 sack of bran, for instance — or masses of cereals held together by the 

 Avebbing made by the flour-moth larvae. An apparatus used by this 

 Department to ascertain this was found to be faulty too late in the 

 year to remedy the defect, and the results of that particular experi- 

 ment, therefore, can not be relied on. However, the matter was given 

 a practical test by exposing a mass of webbing over 2 inches thick, 

 containing live worms, pupa^ (and piobably eggs) of the flour moth 

 to the fumes of the gas as commonly used at the above strength, for 

 over ten hours, the time commonly occupied in a fumigation. As 

 far as could be observed at the time, everything in this mass was 

 killed, and after three months' observation of the same in our labor- 

 atory no sign of the flour moth in any stage was apparent, indicating, 

 possibly, that this gas has a greater penetration than w^e had sup- 

 posed. At the same time, this isolated experiment should not be 

 relied on as certifying absolutely upon this point. 



WOKK AGAINST THE LITTLE RED ANT IN A RESIDENCE. 



The little red ant {Monomorium pharaonis L.) has been a great 

 pest in a large residence in Minneapolis for several years past. Dur- 

 ing the fall of 1905 these ants became so numerous that we were re- 

 quested to try to eradicate them. At that time very few parts of 

 the house seemed to be entirely free from the pests. Flowers, food, 

 or candy left in almost any part of the house would be covered in 

 a few hours. The ants were particularly annoying when they were 



