A GENERAL SURVEY OF THE MAY- 

 BEETLES (PHYLLOPHAGA) 

 OF ILLINOIS 



By STEPHEN A. FOEBES, State Entomologist 



The following discussion is based on a study of the numbers, dates 

 of occurrence, food-plants, and distribution in Illinois of 114,493 May- 

 beetles or "June bugs" belonging to thirty-four species of the genus 

 Phyllophaga, and very nearly all collected by my field assistants in 

 forty-two Illinois counties during six of the years from 1907 to 1913, 

 no collections being made in 1912. Occasional use is also made of the 

 data of 4,224 specimens additional, obtained in central Illinois in 1905 

 and 1906, and two tables of the most important of these collections, 

 that made at Urbana in 1906, are printed with the other statistical 

 summaries. It is the general object of these studies to distinguish the 

 several species of Illinois May-beetles (the parents of the white-grubs) ; 

 to see which of them are numerous enough anywhere and at any time 

 to be notably injurious in the grub stage to agriculture and horti- 

 culture; to learn the food, when in the beetle stage, of these more 

 injurious species; and to learn, so far as practicable, what are the 

 conditions favoring the increase and decrease in numbers of each 

 species, in the not unreasonable hope that a knowledge of these funda- 

 mental matters may help, now or eventually, to a solution of the old 

 and very difficult problem of the control of economic injuries by the 

 white-grubs. I have also had especially in view the food habits and 

 preferences of our most abundant May-beetles, as related to the choice 

 of trees and shrubs for roadside planting and for the home premises. 

 Other studies of mine have clearly shown that fields and lawns in 

 the neighborhood of trees upon which May-beetles may feed, are much 

 more liable to injury by the white- grubs than those at some distance 

 from such trees, and it is important, consequently, that those con- 

 cerned should know what kinds of plants offer special inducements to 

 an infestation of their premises by those destructive insects. 



Location of the Collections 



Of the forty-two counties from which collections were obtained 

 thruout the state, nine were in northern, eighteen in central, and 

 fifteen in southern Illinois, those in each section extending well across 

 the state. 



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