. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 4 BULLETIN" 104, U. S. DEPARTMENT OF AGRICULTURE. other plants, but more especially through breeding. Eggs are deposited and hatched on the spikes themselves. On hatching, the young larvae quickly seek the flowers, doubtless attracted by the pungent fragrance of the nectar, and literally wallow in the nectar and pollen, avidly drinking the one and voraciously devouring the other. Observations covering five seasons have shown that several species of Thysanoptera visit beet flowers and that the number of individuals
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 4 BULLETIN" 104, U. S. DEPARTMENT OF AGRICULTURE. other plants, but more especially through breeding. Eggs are deposited and hatched on the spikes themselves. On hatching, the young larvae quickly seek the flowers, doubtless attracted by the pungent fragrance of the nectar, and literally wallow in the nectar and pollen, avidly drinking the one and voraciously devouring the other. Observations covering five seasons have shown that several species of Thysanoptera visit beet flowers and that the number of individuals varies greatly with the locality and general environments, notably with the crops in the vicinity. At Jerome, Idaho, in 1913, on land only recently cleared from sagebrush, thrips were rather scarce, although somewhat abundant in alfalfa in near-by fields. These insects have also been seen in moderate abundance on seed beets in Indiana and Michigan. THRIPS AS POLLEN BEARERS. The writer has been able to discover in the literature very little reference to thrips as a pollen bearer and no proof of its ability to bring about the fertilization of flowers. Darwin was familiar with the visits of thrips and kept hi mind the possibility 'that they might gam entrance through his nets. Hermann Miiller 1 records their occurrence in the flowers of several genera and species, but does not mention beets. In a paragraph on Thysanoptera he says that "probably few flowers, if any, are altogether exempt from their visits, and though they have seldom been detected in the conveyance of pollen, yet from their great abundance, their value as fertilizers must not be overlooked. It is almost im- possible to exclude these tiny insects by means of nets. The Thysan- optera seek both pollen and honey. They seize a single pollen grain in their mandibles and convey it to the ; Uzel,2 in Bohemia, has noted the visits of several species of Thy- sanoptera among sugar and stock beets, but adduces
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