8o 



The Book of Bugs. 



Fig. 15. The stem- 



forth living young, all females, and continues during her 

 life-time to add to her family from two to eight daily. 

 These in turn become mothers when eight days old. 



The stem-mother may live to see her 

 great-great-granddaughters. 



By the time the third generation 

 appears the hop-vines are up. They 







must get at them, so this third genera- 

 tion of virgin-born females, cleverly 

 enough, comes out in wings and 

 takes flight to the new field of opera- 

 tions. There they jab their beaks 

 mother of the hop-plant into the plants and suck the juices 



louse; enlarged antenna , 11 -r- 



above automatically. Jvery once in so 



often, as if actuated by a common 



impulse, they tilt themselves up on their noses and dis- 

 charge a shower of sweet liquid ' from glands in their 

 abdomens. Ants are very fond of this liquor. By the 

 time hop-picking is well under way, wings that had been 

 as out-of-date as puffed sleeves are with us, come in 

 again and are all the rage. It is about time to get back 

 to the plum tree. Later in the season there is a genera- 

 tion exclusively of males. They set the sponge, so to 

 speak, of next year's baking and perish. 



I am reminded in this connection of the famous saying 

 of Michelet that so wise is the governance of this world 

 that the most destructive insects are those most relished 

 by birds. This sounds a good deal as if he had had to 

 say it in order to hold his job in some small denomina- 

 tional college, where the professor of geology has to 

 keep his mouth shut about the doctrine of evolution. It 

 would be ever so nice if it \vere only true, but I never 

 heard that the French birds got very fat eating the 

 phylloxera, or if they did they could not keep up with 



