30 



THE AMERICAN BOTANIST 



beetle or June-bug, a clumsy, big, bro^A-n, buzzing beetle that 

 bumps about against the ceiling and ultimately falls into the 

 lamp if this is possible. This interesting specimen is the parent 

 of the white grub which one discovers so cunningly curled up 

 in the soil when spading the kitchen garden. It takes the white 

 grub two years to become a May-beetle, but it takes the ]\Iay- 

 beetle only thirty-one days to become a June-bug, an automatic 

 advance, as it Avere, facilitated by the calendar. AMiile the 

 grub is groAving up, it dcA'Ours the roots and other under- 

 ground parts of plants and is especially fond of potato and 

 straAvberry plants. In laAvns and pastures, colonies of these 

 grubs often ruin the soil over large areas. The adult beetles 

 feed on the leaves of trees and shoAV a decided preference for 

 oak, poplar, apple, AvilloAv and hickory, though nearly all of 

 the broad-leaA^ed trees are attacked. An exception is made in 

 the case of the box elder ; CA'en a June-bug has no use for that, 

 though it does loA'e that other tree-Aveed, the Carolina poplar. 

 In Europe there are only tAvo species of June-bugs, but Avhen 

 Ave go in for anything on this side, Ave spare no expense. The 

 State of Illinois, alone, has thirty-four species. AA'e have no 

 record of the number in other States but haA'e an idea that 

 there are ahvays enoug'h to g'O around. 



Leaf-]\Iargin and Exa^iroxmext. — The beginning stu- 

 dent of botany seldom regards toothed and notched leaf-mar- 

 gins as anything more than convenient means of identifying 

 his specimens, but recent studies have shoAvn the nature of the 

 leaf-margin to be intimateh' related to the distribution of 

 plants. A survey of the dicotyledon plants of the Avorld shoAvs 

 an overAvhelming number Avith entire leaf-margins in tropical 

 and frigid regions, Avhile those Avith notched and toothed mar- 

 gins, though represented in these regions, are much more abun- 

 dant in temperate climes. AMienever a temperate flora con- 

 tains Avoody species Avith entire leaves they are almost invaria- 

 blv extensions from tropical or cold regions. In tlie flora of the 



