From the above measurenients of grubs, it will be seen that larvae 

 of this May-beetle may be at once distinguished from those of Phyl- 

 lophaga vandmei, in whatever instar, by simply measuring the diame- 

 ter of the head with a sliding callipers. Furthermore, by means of 

 the head measurements and a consideration of tlie locality, the grubs 

 of any of the five species of j\Iay-beetle occurring on the Island may 

 be easily distinguished, one from the other, without the need of labor- 

 iously studying minor characters, which at best are variable. 



PtTPA AND PRE-EMERGENCE OF ADTTLT. 



The length of the pupal stage of Phijllophaga giKDiicana w&h 

 determined as 22 days, recorded from a single pupa. The meas- 

 urements of this pupa were as follows : length 18 millimeters ; width 

 at middle, 7.9 millimeters. 



The pupa may be very readily distinguished from that of P. van- 

 dinei by its smaller size, and its somewhat darker color. 



As has been stated before, the length of time spent by the adult 

 of this species in the pupal chamber before emergence is supposed 

 to very often exceed a month, and may perhaps, in cases where the 

 adult issues during November, approach or even exceed three months. 

 No experiments were conducted to determine this fact. In confine- 

 ment, however, three adults issued during late November and early 

 December; and it is well known that in the field beetles of this 

 species never emerge from the soil during these months. 



Food Plants of Adult. 



This species, as was mentioned in the beginning, frequents the dry 

 upland pastures and brush land, and is not often encountered in cane 

 fields. It is natural, then, that its food plants should diifer con- 

 siderably from those most palatable to the sugar-cane May-beetle (P. 

 vandinei). Among the few trees upon which both species are known 

 to feed may be mentioned the flandioyant, casuarina, salcilla {Schra)i- 

 kia portoricensis) , guacima, and tamarind. 



.Among those trees and bushes which are fed upon peculiarly by 

 this species, and are rarely or never eaten by the sugar-cane May- 

 beetle, are the guava {Psidium guayava), the ucar tree {Bucida huce- 

 ras), the l)lack sage {('ordio, cgUndrostachya), Lantana camara and 

 Hamelia sp. All of these are favorite food ])lants of the beetle. 



Flight and Attraction to Light. 



The flight of this species wfis observed in a rearing cage at Santa 

 Rita on April 28. 1915. The first beetles took flight from the soil 



157 



