488 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



The first series of experiments was to determine to what extent the 

 young of the black scale, Saissetia olecv, might be captured on tangle- 

 foot flypaper. After the paper had been exposed to the sun for two 

 or three days, it was found that the sticky material became very hard 

 and firm. It was at first thought that this fact would make the paper 

 of little value for entangling the scales, but upon examination, it was 

 seen that many were captured nevertheless. It should be noted, 

 however, that in the discussion that follows, all time records are for 

 but two or three days, the limit of effectiveness of the material, regard- 

 less of how long the sheets might have been exposed. If the tangle- 

 foot had remained effective longer, there would, of course, have been 

 many more scales captured. On the other hand, there is some little 

 advantage in the handling and examination of the sheets occasioned 

 by the hardening of the material. The sheets were placed in different 

 situations and at different distances from infested trees as indicated 

 below. 



The Capture of Young Black Scale on Tanglefoot Sheets 



The twenty-one sheets put out on June 28, 1915, entrapped a total 

 of 7,262 scales or an average of 346 scales for each sheet. Only four 

 sheets fell below 100, while the maximum number was 1,056. The 

 distance from the infested trees ranged from 10 feet to 450 feet, the 

 average distance being 70 feet. The prevailing direction of the wind 

 was from the west and southwest. On the sheets facing west, the 

 average for each sheet was 408. On those with a south exposure, the 

 average was 241, north exposure, 210, and east exposure, 162. How- 

 ever, because of the difference in the number of sheets with the differ- 



