fiO 



sonic of the white varieties, which oradually deepens and 

 spreads u]) to the very limits of the uolden yeUow spot, 

 without encroaching one hair upon its territory. Notice 

 two |)()ints : the tiower change is from white to blue, just 

 as is seen in Pansy, with not a hit of red intervening; also 

 that sometimes the change is so innnediate that it is from 

 yellow to hhie, no wdiite even being noticed. 



Anything that arrests the attention may be a valuable 

 guide for certain purposes ; the stamens of the fragrant, 

 fuU-chistered, little white Rosa multitlora are at tirst of a 

 bright yellow, by the second day or I)efore they turn a dark 

 brown, so that the yellow and the l)rowm centres are quite 

 distinct in the same cluster. The bees always take the 

 yellow centres and pass the others by. 



Example 3. — In violet-)iurple Ponlejhria ^ pickerel-weed, 

 the bum))le-bee always Hies directly towards the t\vo-loI)ed 

 yellow dot on the upper petal, against which he presses his 

 head as he sips the nectar. 



In this instance it is the insect's head and not his feet that 

 causes the irritation, preserving most likely the original 

 color of the flower, the dark i)urple l)eing the more recent. 

 It is quite possilile also that buttertlies are concerned in 

 this particular marking, for the })roniinent little feelers 

 between their eyes touch at exactly this place as they 

 extract the nectar ! 



Example 4. — In GalantJius, the snow-drop, and Leuro- 

 iu/H, the snow-Hake, we have examples of green colored 

 honey guides; in the former of these flowers which are 

 both white, the three short inner segments are green on the 

 inside where the insects enter ; m Leucoinn) the bee clings 

 tirst to the drooping tips of the sei)als which are green 

 colored, before he turns up into the Hower, These green 

 tips, all the rest of the flower being white, were caused by 

 the bee in the same manner that the yellow spot of Iris 

 and the Indian-red of Tropteolum were i)roduced, but the 

 original color of Leucoium was green I 



