[BS] Darwin's Fertilization of Orchids, p. 2; Lubbock's Scientific Lectures, p. 8.

[BT] Sir John Lubbock's Scientific Lectures, p. 3. Mr. Darwin refers to Fritz Müller's papers as reported in Botanische Zeitung, 1869-70. [Appendix IX.]

[BU] The Various Contrivances by which Orchids are fertilized by Insects, 2d ed. p. 293.

[BV] Fertilization, p. 5.

[BW] Fertilization, p. 12.

[BX] Fertilization, p. 102.

[BY] Ib. p. 113.

[BZ] Fertilization, p. 44.

[CA] Scientific Lectures, p. 31.

[CB] Fertilization, p. 2.