INSECT PESTS OF OHIO SHADE AND FOREST TREES 237 



known to all who till the soil. (See Plate XXXIII, Fig. 2.) The 

 pupae are robust with pointed body and folded appendages showing 

 plainly on the underside. 



Life history and habits. — The eggs are laid on the roots of 

 plants usually in considerable masses. Upon hatching, the tiny 

 grubs begin feeding upon the plant roots and remain beneath the 

 surface of the soil for a period of 2 years or more. At the end of 

 larval growth they form an earthen cell and transform to the pupal 

 stage. After a variable length of time, the beetles emerge and 

 make their way to the surface of the soil, whereupon they take wing 

 and fly to the treetops to begin feeding. This period of emergence 

 is during May and June, which accounts for the popular name of the 

 insect. Soon after emergence the insects pair and, after a few 

 weeks of existence in the adult stage, during which egg-laying 

 occurs, they die. It will thus be seen that about 3 years' time is. 

 required to pass through the various stages from egg to adult. 



During the adult stage the insects are nocturnal, spending the 

 day in the grass fields in which they lay their eggs and in the 

 evening flying to their feeding grounds in the treetops. Before 

 morning they return to their grassy retreats. 



Nature of work. — The injury caused by these insects is two- 

 fold. The type which occasions the most severe losses is that of 

 the feeding lai"vae on the roots of plants and upon root crops. Corn 

 and potatoes are more severely injured than other crops, but from 

 the forestry standpoint the injury inflicted upon tree seedlings in 

 nurseries occasionally is serious. 



The greatest harm done to trees, however, is the destruction 

 of the foliage by the night raids of the beetles. Not infrequently 

 it is a source of much mystery to the uninitiated when the trees 

 in May and June are seen to be badly mutilated and no trace of a 

 depredator can be found. In severe outbreaks of the beetles, trees 

 may be stripped of their foliage, as frequently happened during the 

 flight of 1914. A glance at Plate XXXIII, Fig. 3, conveys this idea 

 fully. Isolated trees or trees growing in small plots are attacked 

 with greater severity than when otherwise situated; as are also 

 trees growing near rather than distant from grass-lands. 



Food plants. — The larvae feed upon the roots of a wide range 

 of plants, and the adults on almost an equally wide range of decidu- 

 ous trees. Willows and poplars frequently are attacked with great 

 severity as are also elm, oak, ash, etc. Rarely do trees succumb 

 from May-beetle defoliation, but the injury thus sustained detracts 

 from their beauty and usefulness and renders them more likely 

 subjects to injury from subsequent depredators. 



