ExrERiMi^:iM\s AT lUiocKroirr. 17 



ground, the licaltliy ])eais at tliis time being about one-foui tli of an 

 incli in diameter. By the end of another week, when the thrifty fruits 

 have attained a size of one-half to tliree fourtlis of an ineli in diameter, 

 it will be observed that a secoud set has fallen behind. These, after 

 attaiuing- the size of a pea, stop growing, while tlie rest eontinue. 

 These two periods of falling are fairly distinct, and after tlie second, 

 which occurs about fifteen days after pollination, but little dropping of 

 the fruit ordinarily occurs. A few pears may fall off later than this, 

 but the general average of fruitfulness of a tree may be determined 

 by tliat time. At Eochester in the spring of 1892 a good many pears 

 fell off after they had passed the second period of falling and had 

 reached half an inch in diameter, but Mr. Ellwanger, of the firm of 

 Ellwauger & Barry, stated that this was unusual. From this time till 

 autumn the codling moth causes many fruits to fall, and the scab 

 fungus (Fiisicladiimi 2)ijrinum) also destroys young fruits. But these 

 are outside agents and nnist be considered apart from tlie subjectt we 

 are here investigating. 



Each of the four series of experiments will now be taken u]), and the 

 conditions under which the work was done and the methods employed 

 will be described in some detail. As to the results, only such general 

 statements will be given here as will show the connection between the 

 different series. Following the details a synopsis of all the work is 

 presented, in which the data and numerical results are given. All the 

 exj)eriments on each variety are there brought together. 



SERIES I. — EXPERIMENTS AT BROCKPORT, N. Y. 



Plan of the experiments. — The attention I had given to insect visitors 

 of pear flowers previous to the Brockport experiments was limited to a. 

 few casual observations at Thomasville, Ga., in 1890, and to more care- 

 ful and extended observations at Washington, D. C, in the spring of 

 1891. The latter investigations were carried to a point where it seemed 

 necessary to ascertain the value to the pear flowers of insect visitors, 

 consequently in connection with other investigations at Brockport an 

 attempt was made to obtain an answer to this question. For this ]>ur- 

 pose 15 trees were selected, rej)resenting eight different varieties. 

 Seven of these trees, consisting of Bartlett, Anjou, Winter Nelis, Clapps 

 Favorite, Angouleme, and two the names of which were not known, were 

 situated in the town of Brockport, in two gardens, which were separated 

 by a narrow street. The 7 trees were all in sod, but 4 were situated 

 on the border near cultivated ground. All were apparently well fed and 

 in good vegetative condition. The remaining 8 trees, 2 Angoulemes 

 and 6 Seckels, were located in an orchard of dwarf trees, consisting 

 solely of these two varieties, planted in alternate rows, and situated 2 

 miles from the trees in the village. The Angoulemes and Seckels were iu 

 1187()— Xo, T) 2 



