multiplication of l)eotle posts of this sort, and tliat it is grown con- 

 tinuously year after year on the same ground, without any rotation 

 of crops, render the control of these insects a very serious and very 

 difficult problem. Prior to 1918, the year that the present studies 

 were inaugurated, a considerable amount of experimentation had 

 been made by different i)arties toward controlling the whitt^-grubs 

 in cane fields, (1) by putting baits, poisons, or fumigants into the 

 soil, (2) by spreading various deterrants on the soil near plants to 

 prevent laying of eggs, (8) by flooding the land with water, or (4) by 

 killing the adult beetles by means of poison sprays applied to tlie 

 foliage. The results of many of these experiments were negative ; 

 and such of them as gave promising results proved inexpedient be- 

 cause of the high cost of materials or nf application. 



It became increasingly apparent that no hope of a solution of 

 the prol)lem could come from an application of direct methods of 

 control such as these, but that real benefit t(» the cane-growing in- 

 dustry could come only through the employment of broadly outlined 

 cultural methods of control, based upon an accurate knowledge of 

 the insects' life-histories, or perhaps through the introduction of insect 

 or fungus parasites to prey upon the whitt^-grubs. 



Life-history and close field studies of the several species were 

 instituted in ^lay, 1913, and have been continued to the present date. 

 The object constantly in mind has been to determine accurately the 

 length of life-cycles; the time and conditions of oviposition of the 

 eggs; the time of emergence, sexual habits, feeding habits, and habits 

 of flight of the adults; and the inter-relation of these habits and 

 the factors which tend to hasten or retard the fime of emergence of 

 the beetles or to affect the amount of damage. 



A preliminary report by the author appeared in the Annual 

 Report of this Station for the year 1913-14 (23)^ and some addi- 

 tional data in tlic Report for 1914-15 (24). Much of this data is 

 included in the present paper, togethci- with tabulations and graphic 

 charts showing life-cycles, and illustrations showing injury, the early 

 stages, adults and adult parts, parasites, etc., from original photo- 

 graphs. 



^Nletiiods of conli'dl of white-grubs, and results of the intro- 

 duction of parasites, will be discussed at lengtli in a later number 

 of this i)ublication, when certain expeiiinents and tabulations now 

 in progress will have been compleled. Detailed studies of the larvaJ 

 (or grub) and pupal stages, now being made. l)y wliich it is hoped 



' Rpferpnpp is niiidi- liy luiinlni- l<i ■■I,iti>i-,'iliirc cited." i)i>. S8— 89. 



48 



