Grass Insects 



567 



on which they feed throughout the season. The grubs of some 

 species reach maturity at the end of the second summer, but in 

 the case of our more common species the grubs are not full grown 

 at that time. In the latter case the grubs again descend into the 

 soil for hibernation and return to the grass roots in the spring of 

 the third year. After feeding for a period they become full 

 grown in June or July. The grub then constructs aji oval earthen 

 cocoon in which it transforms to a delicate whitish pupa. The 

 insect remains in this condition until the latter part of the summer 

 and then transforms into a beetle. In this condition it remains 

 ill the earthen cell until the following spring, when it emerges 



(Slingerland photo) 



Fig. 610. A June Beetle With Wings 

 Expanded, Natural Size. 



from the ground. While certain species emerge the second spring 

 after the eggs are laid, and a few do not emerge until the fourth 

 spring, the greater number of our injurious species do not emerge 

 until the third spring. For instance, in the last case the young 

 grubs that hatch from eggs laid in the spring of 1917, feed until 

 the fall of that year, hibernate during the winter of 1917-18, feed 

 again through the summer of 1918, hibernate again as grubs 

 during the winter of 1918-19, complete their growth, pupate, and 

 transform to beetles that season and hibernate as beetles during 

 the winter of 1919-20; the beetles emerge in the spring of 1920: 

 It will be seen from the foregoing account that the grubs are 

 most destructive during the second season, because it is then that 

 they feed for the longest period and make their greatest growth. 

 The first year the grubs feed only during the latter part of the 

 season and are very small. The third summer they feed only 

 during the early part of the season and only enough to prepare 

 themselves for pupation. 



