354 FoRTF-sixTH Report on the State Museum 



'' If this method could be made equally effective with you, it would 

 certainly pay to resort to it. The expense of following the emulsion 

 with repeated water application could, I suppose, be saved, if the 

 kercsening should be done before a rainy spell. 



"At what depth do you find the grubs at the present time, and what 

 nursery stock do they mostly infest? 



" I wish that you would try the emulsion upon an area of some 

 •extent, and, after the rains, dig for the grubs, and see what the effect 

 has been. The low cost of kerosene would permit of its fi'ee use if 

 found to be effective. You probably have the formula for the prepara- 

 tion of the emulsion — if not I will send it to you." 



In reply to the question of the nursery stock attacked, answer was 

 made: "We raise mostly roses, ornamental shrubs, and grapevines. 

 These grubs attack all of our stock; we even find them at the roots of 

 two-year-old apple, peach, and plum trees, but they do the most damage 

 to the roses. We would like to try the kerosene emulsion, and, if you 

 will kindly St nd us the formula, we will do so, but fear that it may 

 kill the young rose-bushes as well as the grubs." 



The formula for the emulsion was sent as requested, but no report 

 of results from its use has been received. 



As the Entomological collection of the U. S. National Museum at 

 Washington, D. C, contains more larval Coleoptera than any other 

 ' collection in the United States, examples of the grubs noticed above 

 were sent by me to Dr. Riley, at Washington, in the hope that they 

 could, by comparison, be at least generically determined, but unfortu- 

 nately, by some mishap, they failed to reach their destination. 



The enormous aggregate of losses in garden and field crops inflicted 

 "by white grubs is offered as a reason for appending to the above some 

 additional words in relation to this destructive class, which will be 

 found of economic importance in directions that will be pointed out. 



Professor Forbes, State Entomologist of Illinois, has recently Avritten:* 

 '" The white grubs are among the immemorial enemies of agriculture in 

 both worlds, but in neither Europe or America has the problem pre- 

 sented by their injuries on the farm and in the fruit and vegetable gar- 

 den received a satisfactory solution." 



While still unable to recommend entirely effective, simple, and inex- 

 pensive methods for destroying these larvae when infesting grass land 

 or other large pieces of ground, we now know through the labors of 

 Professor Forbesf so much of the life-history of the more common 

 ■species allied to the May-bug, Lachnosterna /usca, that we may say, 



* Seventeenth Report on the Insects of Illinois, 1891, p. 30. 

 -^ On the Common White Grubs, loc. cit., pp. 30-53, plate iv, figs. 1-7. 



