This experiment shows that small insects are efficient pollinators of sweet clover and that the plant to which all insects had access produced an average of only 3.7 pods to the raceme more than the one inclosed in the cage. As these plants were growing close to a strip of timber and some distance from a field of sweet clover, it is probable that more small insects worked on the flowers than would have been the case if the cage had been located in the center of a field of sweet clover. Though these results show that small insects are able to pollinate sweet-clover flowers freely, it is very doubtful whether insects of this kind would be numerous enough to pollinate sufficient flowers in a large field of sweet clover for profitable seed production. The honeybee is the most efficient pollinator of this plant, and it is believed that in many sections it is responsible for the pollination of more than half of the flowers. SUMMARY OF INSECT-POLLINATION STUDIES. The data secured in the different experiments where sweet-clover flowers were subject to insect visitation at one time or another are presented in detail in Table V. Table V.--_Summary of the insect pollination studies conducted at Arlington, Va., and Ames, Iowa, in 1916._ ----------+-------+-------------------------+---------------------------- | | | Number of-- |Number | +--------+---------+--------- Location. | of | Method of treatment. |Racemes.| Pods |Pods per |plants.| | |produced.| raceme, | | | | | average. ----------+-------+-------------------------+--------+---------+--------- Arlington.| 1 |Check--subject to insect | 196 | 4,013 | 20.47 | | visitation at all times.| | | Ames. | 1 | do. | 239 | 9,943 | 41.60 Arlington.| 3 |Protected from all | 904 | 577 | .63 | | insects. | | | Ames. | 12 | do. | 2,370 | 653 | .27 Arlington.| 3 |Visited by night-flying | 723 | 2,720 | 3.76 | | insects only (cage 1). | | | Do. | 1 |Visited by night-flying | 227 | 152 | .67 | | insects only (cage 2). | | | Ames. | 1 |Visited by night-flying | 486 | 8,024 | 16.51 | | insects only. | | | Arlington.| 2 |Visited by day-flying | 544 | 11,397 | 20.95 | | insects only. | | | Ames. | 1 | do. | 418 | 17,186 | 41.11 Do. | 9 |Protected from all | 1,594 | 502 | .31 | | insects. | | |