/'()/,/ /.V.I y/('.v 



189 



In- a i)crci-i)li<>ii of ihc lastcs and likini^^s of insect 

 life, aiul \\c sliall -raduall)- learn to e.\-i)ect to .sec 

 certain insects on the llowers they speciall)- freiiuent. 

 I would call attention to the interesting;- fact that 

 if one aiienc)' fails to effect pollination, another is 

 adojjted in order to attain the desired end. Thus, 

 when the flowers of tiie 

 common bartsia first open, 

 the\- are \ isited b\- insects ; 

 but, in the later sta<^es of 

 flowerinL;-, the pollen is blown 

 out b\' the wind, and the 

 neighbouring; stigmas thus 

 become pollinated. We see 

 in the arrangement of the 

 flower (jf the St. John's \\-ort 

 (^Hypericuiii) a perfect t\'pe 

 of this proxision against an\- 

 possible failure of pollination. The stigma is sur- 

 rounded by groups of stamens of unequal length ; 

 those in the centre nearest to the stigma arc as long 

 as the style it.self, whilst tho.se on the outside are 

 short, and the.-e shed their pollen first, whilst those 

 in clo.se contact with the stigma shed their contents 



llYl'KKlLr.M. 



