26 
Colorado Experiment Station 
were divided. The flowers on half of each plant were “tripped” by 
hand. The other half of the flowers of each plant were unmolested. 
The results here were very similar to the results under the covering 
of screens. Some produced seed and some did not. There was 
practically no difference in seed yields resulting from hand 
“tripping” of the flowers. Observations have been carefully made 
to try and determine if the flowers on plants that were proliflcally 
setting were any more likely to be “tripped” than flowers which 
were failing to set seed. While some plants seemed to have more 
“tripped” flowers than others, it could not be seen that the 
“tripped” flowers were more inclined to set seed. Many flowers 
were observed which did not “trip.” They remained untripped until 
the bloom withered. Yet many such flowers did set seed. There is 
a possibility, of course, that the “tripping” may have occured when 
the bloom began to wither. 
The presence of large numbers of the small insect' know as 
A very good typical representative of the northern or hardy type of alfalfa. 
