The chief purpose of the investigations described in this paper was to determine the relative pollen constancy of the various insect pollinators of the apple. In addition to the hive bee, these proved to be solitary bees belonging to the genera Halictus and Andrena, with Bremidae and various Diptera playing a minor role. It is pointed out that apparent flower constancy depends a great deal upon availability and that almost any result may be obtained by choosing certain periods in which to make tests. The results, based on analyses of the pollen loads of bees captured in apple blossoms, place the hive bee first as regards the number of pure loads, followed by Halictus, with Andrena a poor third. Taking into consideration the results of the entire season, and the analyses of bees from different sources of pollen, Halictus came first in these particular tests, but the difference is not considered significant. The supposed superiority of the hive bee from the standpoint of constancy does not appear to have been proved. Both Halictus and the hive bee, however, evidenced a significant superiority over the Andrena species studied.