TABLE OP CONTENTS 



Page 



IntrgductioM-- ■ 3 



Description of the Alfalfa I'lower 4 



Condition of the Elowers in Alfalfa Eields 6 



Description of the Experiments and Discussion 



of the Results 7 



Comparative proportions of flowers producing 

 seed under natural conditions when protected 

 from insects and when artificially tripped 7 



Effect of protecting the alfalfa flowers 



from sun and wind \^y a single thickness 



of fiiosquito netting, hut with provision 



for reads'- access of insects 14 



Comparative numher of pods and seeds forming "* 

 under natural conditions ftom flower^ 

 which have heen tripped and from flowers 

 which have not been tripped--- 16 



Effect of fertilization with pollen of 

 different degrees of relationship 19 



Pods formed when stigma and pollen do not 

 come into contact with any ohject when the 

 flower is tripped • ■ ■ ■ 26 



Pods and seed produced from automatically 

 tripped flowers 28 



Pods and seed developing from untripped 

 flowers --~.~. — . .^ 40 



Effect of tripping alfalfa flowers 

 mechanically --■ 40 



Period during which alfalfa flowers may 



he pollinated ■ 42 



Efficiency of Various Insects in Causing 

 fertilization of Alfalfa Flowers 44 



Domestic Honeybees, bumblebees, and wild 



bees ( Megachile spp . ) 44 



(1) 



