THE WHITE-GRUBS. 23 



oak-tree, especially white-oak, the foliage of which they seem 

 to prefer, and here they gather in very large numbers and 

 their presence is soon indicated by the ragged appearance 

 of the foliage of the trees. This time of feeding is followed 

 by a love-feast, and numerous pairs w^ill be found mating if 

 we goto the trouble of investigating the oak-trees during the 

 night. Early in the morning all beetles leave the tree and hide 

 in the ground by digging their way into it to the depth of 

 one or two inches; here they rest during the day but leave it 

 at dusk to repeat their destructive operations for a number 

 of nights. Meanwhile the eggs become large and have to be 

 disposed of, and for this purpose the females dig their way 

 among roots of plants and deposit here and there these large 

 and almost transparent objects. To obtain such eggs it is 

 only necessary to gather a number of beetles and to put 

 them in a flower-pot filled with moist and loose soil. A 

 large number of eggs are laid, which soon hatch into small 

 and almost transparent larv£E that feed upon the roots of 

 many kinds of plants, but especially upon those of grasses. 

 These young larv£E are very tender, and resemble an irregu- 

 lar drop of water surrounded by a very delicate skin. As 

 they grow older they become whitish, with brown heads 

 and legs, and possess the well-known form of the so-called 

 white-grubs shown in the illustration (fig. 16, plate II). 

 After feeding one or two years, according to the species, they 

 reach their full size, and now transform into pupae, which 

 already indicate in a general way the future form of the 

 adult beetles. Here in Minnesota the pupa is formed late in 

 summer or early in autumn, and changes soon afterward to 

 a beetle, which, however, never leaves the ground until 

 spring. It is not at all uncommon that such beetles are 

 plowed up in autumn; when thus exposed they are very 

 pale in color and very much softer than in spring, showing 

 that they are not yet entirely mature. If exhumed during 

 autumn they gradually w^ork their way back into the soil, 

 but do so in a very slow and awkward manner, and thus 

 are so much exposed in the shallow and poorly made cell 

 that they are killed by rain and cold. If the cells they form 

 around themselves as larvae for hibernating purposes are not 



