240 



erroneous and misleading in some important particulars, and that agri- 

 cultural practices based on this inaccurate biography must be largely 

 without beneficial eflect. 



If 1 were to say that the white grub lives for three years in the earth, 

 counting from the May or June when the eggs are laid ; that the grub 

 or larva gets its growth in its third autumn, hibernates in the earth 

 without transforming, pupates in the third spring of its life, and pres- 

 ently emerges as an adult. I should repeat in substance what has been 

 many times said before, and my statement would probably pass even 

 now without serious challenge. But this account would be quite in- 

 accurate, at least as to the period of maturity and the time of trans- 

 formation of the great mass of our white grubs, and might lead to un- 

 fortunate practical mistakes. 



In fact, all the species of Lachnosterna which I have observed (to 

 which genus the great majority of these grubs belong) get their full 

 growth in spring and early summer, pupate in summer and early au- 

 tumn, change in the earth to the adult beetle in fall, and hibernate there 

 in that stage without escaping, finally crawling out of the earth for 

 their brief life as " June beetles " in May or June, or rarely in July. 



One practical bearing of this difference in history is easily seen. If 

 the first account were correct, ground which contained full grown, act- 

 ive, and destructive grubs in l-te summer and fiill might always be 

 safely planted, so far as the grubs were concerned, to corn or potatoes 

 or any other of the numerous crops subject to their attack, since by 

 spring the insects would be too far advanced towards pupation to do 

 any further injury ; but in fact this is far from being the case, for a 

 grub active in fall will also, if nothing interferes with it, be destructive 

 in spring and well on towards or into the summer, and will thus have 

 time the following year, before reaching the term of its larval life, to 

 completely destroy either corn or small grain. 



Furthermore, if the first account were correct, a farmer who finds his 

 ciop destroyed by full-grown grubs in spring need not hope to raise 

 anything not grub proof on that ground that year; while the truth is 

 that he may expect to see his field practically deserted by his enemies 

 by July or even by late June, and may consequently plant some time 

 previous to that without fear of harm. 



The current and most authoritative statements of the life history of 

 the white grubs are incomplete and more or less contradictory. 



Dr. Harris says that "the habits and transformations of the common 

 cockchafer of Europe have been carefully observed, and will serve to 

 exemplify those of the other insects of this family, which, as far as they 

 are known, seem to be nearly the same," and continues with a compiled 

 account of the history of the European species* to the effect that the 



•Several standard European authorities give quite a different account of the trans- 

 formations of the European cockchafer from that quoted by Harris. Ratzeburg, 

 Maurice Girard, and Taschenberg give for it a life history esseutially like that of 

 Lachnosterna, as here established. 



