1922] Folsom: Pollination of Red Clover 183 



were then allowed to dry, and were examined for seed July 1, 

 by Mr. Otanes and myself. From 789 florets (not counting 

 undeveloped florets that could not have been pollenized) we 

 found 171 seeds. In other words, 21 per cent, of the flowers 

 had been pollenized by Tetralonia dilecta. 



As a check experiment, red clover plants with heads in bud, 

 but not as yet in bloom, were planted in two flower pots, 

 covered with wire cages and placed out of doors, just as in the 

 preceding experiment, but no bees were put into the cages. 

 After three weeks, when the heads were examined for seed, 

 the first cage contained 357 florets and no seeds; the second, 

 287 florets and no seeds. 



Tetralonia dilecta, abundant until the middle of June, 

 became rare by June 30, but a second species of bee soon 

 appeared on the scene and engaged our interest. 



2. Melissodes bimaculata LeP. This black species appeared 

 July 5, was common July 7 and 12, but was falling off in 

 numbers July 21. M. bimaculata, swifter of flight and more 

 alert than T. dilecta, worked actively on clover blossoms in the 

 field. Specimens taken from clover heads showed much 

 pollen, undoubtedly that of red clover, on the mentum, some 

 pollen on hairs adjacent to the mentum, and considerable 

 pollen among the hairs under the eyes. 



As before, red clover plants with unopened heads were 

 potted July 12, and covered with a wire cage. July 14, several 

 heads being partly in bloom, I placed seven individuals of 

 Af. bimaculata in the cage at 2:30 P. M., and one of these w^as 

 working on the heads ten minutes later. July 15, six of the 

 bees had died. July 16, Mr. Otanes put in eleven more bees; 

 and July 19, five more, some of which were seen to work on the 

 flowers. In all, twenty-three bees had been introduced. 



As several bees had apparently been pollenizing florets, we 

 expected to get some seed, at least; but when the dried heads 

 were examined by Mr. Otanes, August 4, the 216 florets that 

 were present yielded only two seeds. Thus the results of this 

 experiment were negative. In a second experiment, however, 

 the results were different. 



In this experiment, plants with unopened heads were potted 

 and covered with a cage July 21. July 23, fifteen specimens of 

 M. bimaculata were put into the cage; and July 25, sixteen more. 

 Many of these bees were seen working on the flowers. 



