456 



Bulletin No. 116. 



[Aiigust, 



seemed to prefer as food. The beetles were gathered by shaking 

 them from the trees at night and picking up those which fell to 

 the ground. 



The following table gives the results of these collections made 

 at Urbana from Carolina poplar (cottonwood), willow, oak, and 

 elm, on twenty-six different nights between May 14 and June 28, 

 1906. 



Comparative Collections of Lachnosterna from Food 

 Plants. Urbana, 1906. 



From the foregoing table it will be seen that poplar (cotton- 

 wood) was the' favorite food, 50 per cent, of the specimens being 

 taken from this tree, and that willow follows next with 25 per cent., 

 oak with 18 per cent., and elm with 7 per cent., poplar and willow 

 together yielding 75 per cent, of the insects. Apple leaves were- 

 often eaten freely, but no trees were suitably situated for experimen- 

 tal field-collecting, and hence no comparative records were made 

 which included apple. Apple orchards in the southern part of the 

 state have been reported by assistants as sometimes almost stripped 

 of their leaves. This was notably so in Jackson county in 1904. 

 The pecan- and persimmon-trees of southern Illinois often suffer 

 severely by having their foliage eaten by the beetles. 



Certain species of the beetles exhibited marked preferences in 

 the choice of food. L. hirticula, ilicis, and tristis had a special liking 

 for oak, the last named being taken from no other tree. L. implicita, 

 gibbosa, fusca, and rugosa were most abundant on poplar, rugosa 

 seemmg to avoid oak and willow. Not enough specimens of L in- 

 versa were taken to warrant conclusions concerning its preferences 



All of the May-beetles taken at lights in the open fields at night 

 m 1906 at Elliott, Ford county, and at Urbana, Champaign county 

 were carefully dissected and the contents of the alimentary canals 



