R A. Harper Gray 49 



the factory and found a few Psocids mostly near the windows — in quite 

 a sufficient number to start another plague of them. It was, therefore, 

 decided to repeat the treatment, but to use fifteen pounds of sulphur 

 instead of ten pounds for the second fumigation. After twenty-four 

 hours' fumigation, the floors were again washed out with carbolic soap, 

 and creosote was carefully poured down, along the cracks in the floor 

 of the loft. The manager was recommended to close up these cracks 

 with cement, after this second fumigation. 



Six weeks afterwards a letter was received from the manager in 

 which he said: "I am pleased to be able to tell you that there has not 

 been a recurrence of the plague of flies," and a recent examination of 

 the buildings showed that the treatment had been successful. The 

 cracks had been closed up with cement as recommended. 



With regard to the probable source of the outbreak it should be 

 mentioned that straw coming in from one of the farms supplying the 

 factory was dirty and in bad condition. The supply of straw from the 

 particular farm was stopped when it was pointed out that this was most 

 probably the source of the trouble, and the writer recommended that 

 care should be taken to secure good clean straw in future. It seems, 

 therefore, likely that the continued freedom from the pest now for 

 nearly six months, is due to this precaution following upon the measures 

 taken against the insects that had succeeded in establishing themselves 

 in the factory. 



Although the Psocids do not attack man, it is interesting to record 

 that in the case of the above outbreak, an eruption appearing on the 

 skin of a child sleeping in a bedroom containing a newly purchased 

 mattress from which the insects were emerging, was not unnaturally 

 attributed by the mother to the presence of the Psocidae. 



Ann. Biol, iv 



