Foraging honey bees (Apis melliferaL.), exposed to birdsfoot trefoil (Lotus corniculatusL.) bloom treated with microencapsulated methyl parathion, continued to display pollen and midgut microcapsule contamination up to 9 days postspray. Nearly 10% of all pollen storage cells examined in combs taken from honey bee colonies exposed to the treated area were found to contain microcapsules.