THE WHITE-GRUBS INJURING SUGAR CANE IN 



PORTO RICO. 



I. LIFE-CYCLES OF THE MAY-BEETLES OR MELOLONTHIDS. 



By Eugene G. Smyth/ Acting Entomologist, Insular Experiment Station. 



The larvffi of all injurious Scarabaeid beetles are known popularly 

 as white-grubs, and those occurring in Porto Rico are injurious either 

 as grub or as adult to the sugar-cane plant, particularly in the drier 

 sections of the Island. An economical way of controlling these grubs 

 is much desired, and it has been with the object of finding some ulti- 

 mate method of control that the intensive studies of the life-histories 

 of the species have been made. 



Up to the present date ten distinct species of white-grulxs have 

 been segregated and studied. Of these, four belong to the genus 

 Phyllophaga (better known as Lachnosterna) and one to the genus 

 PliytaJus in the tribe Melolonthini, Avhile the other five belong to 

 three genera in the tribe Dijnastini, which includes the large rhi- 

 noceros beetles. The present paper deals only with grubs of the first 

 tribe, known as May -beetles, and is an accumulation of data compiled 

 from observations and life-history studies made by the author during 

 the past four years. The work was conducted at the South Coast 

 Laboratory, located near Guanica Centrale, which is in the heart of 

 the district suffering most from the attack of white-grubs. 



The life-cycles and habits of the five species of Dynastids will l)e 

 given in another paper, to follow this. 



The White-Grub Problem. 



Two facts, that sugar is grown over very extensive areas in Porto 

 Rico, under conditions that are ideal for the development and rapid 



' Especial credit is due Mr. D. Ij. Van Dine, the first entomologist of the Experiment 

 Station of the Porto Rico Sugar Growers' Association, and his successor, Mr. Thos. H .Tones, 

 for the initial energy given to the study of the white-griib problem in Porto Rico by these 

 gentlemen. The writer wishes to acknowledge the keen interest in the progress of this work 

 and the cooperation given by Dr. L. O. Howard and Dr. W. D. Hunter, of the United States 

 Bureau of Entomology, and by Dr. S. A. Forbes, of the Illinois State University, and 

 their very efficient aid to those who have been detailed to collect parasites in the United 

 States. Credit is also due Dr. Robert D. Glasgow, of Illinois University, for his patience 

 in examining the large series of May-beetles that have been sent him from the Island and 

 in pointing out characters by which they may be separated. The writer wishes to ihank 

 Mr. John ,T. Davis, of W'est Lafayette, Indiana, for an excellent series of North .American 

 species of Phi/UopJiai/a mounted with genitalia exserted. 



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