•20 



The colors which are quickly changed, either naturally or 

 artificially, are not likely to be lasting, and the latter gene- 

 rally merely anticipate what would naturally take place in 

 due time later. 



The colors of new outgrowths appear to be developed 

 with, and as a part of the new tissue, as in the beards on 

 petals, etc., but such outgrowths are rather of an excep- 

 tional character, whereas spots, streaks, and dots on the 

 plain surface of a petal are of very common occurrence, and 

 are ordinarily remnants of the original color, and have 

 become hereditary. The scarlet zone in the Kaiser Crown 

 tulip, referred to on p. 64 of my Observations, ^vas thought 

 to have been developed directly from a different base-color, 

 but from an examination of additional specimens, it is found 

 that this scarlet zone, like the ordinary honey guide, is also 

 a remnant of a color which once extended upward to the tip 

 of the ])etals ; it therefore affords an additional proof of 

 the correctness of the method above described. 



We have seen by the foregoing statements that insects 

 indirectly change the color of stems and leaves as in galls, 

 etc., and that of flowers by causing new outgrowths as hairs, 

 beards, ridges, crowns, nectaries, etc., and also directly by 

 stimulating a plain surface as in the Chinese primrose ; that 

 their irritations on the petals tend to transfer and diffuse the 

 coloring matter dissolved in the cell-sap, or to concentrate 

 it into spots and streaks according to circumstances — di- 

 rectly, or indirectly by bringing more colorless sap to be 

 colored within the cells, or by so affecting the tissue that 

 when a flower changes color by age, the stimulated part only 

 may change, or if the change is general, then the stimulated 

 part acquires a deeper color. 



