instance, a white flower until tinally a yellow spot be pro- 

 duced upon the white foundation, as a result of the con- 

 tinued insect irritation. The yellow spot would be called a 

 honey guide. 



Prof. Henslow's own words are: ''The spots have been 

 determined by insects " ; " they are srm.plij the direct results 

 of the insects''' ; "one result of a more localized flow of 

 nutriment"; "the insect visitors induced the flower to i)aint 

 the petal with a golden streak." 



The writer's method supposes, for instance, a yellow 

 flower to be visited in like manner, but the irritating effects 

 of the insects result simply in deepening the existing color in 

 the one irritated spot but not otherwise changing it, as in 

 the preceding case. Thus far we have a flower still of a 

 single color but with a part of one petal usually, of a some- 

 what deeper shade. Numerous cultivated flowers are to be 

 met with, in practically this condition, without any more 

 striking feature. To produce a strongly contrasting spot, 

 marking, or entire petal, as is more commonly seen in 

 honey guides, something more is required, which is not 

 within the power of insects to effect, namely, a general 

 change of the basal color, except in the circumscribed and 

 irritated spot before mentioned n-hlch does not change. 

 This general and often profound transformation is not lim- 

 ited to any one color, but a very common change is from 

 yellow to white. Our entire flower would therefore have 

 changed from yellow to white except in one spot, and that 

 spot is yellow because it is part of the original color. The 

 honey guide thus formed has the old color ; Prof. Henslow's 

 honey guide has a neic color. Our flower has a new foun- 

 dation color, while that of Prof. Henslow has the old, origincd 

 one. The methods it will be oljserved are as unlike as could 

 well be imagined: there is absolutely nothing in connnon 

 and yet we are told that our method is appropriated from 

 Prof. Henslow ! 



Prof. Henslow remarks farther reijardino- honev liuidos : 



