THE EGG STAGE. 



The average leugth of egg stage, calculated from the hatching 

 of 146 eggs ill confinement, was III/2 days, the maximum 12 days, 

 the minimum 1014 days. 



The dimensions of the egg are : when first laid — length, 1.5 mm. ; 

 breadth, 1 mm.; when much swollen and shortly before hatching — 

 length, 1.9 mm. ; breadth, 1.7 mm. 



The eggs of this May-beetle are laid singly in the soil, in tiny pits, 

 of about three times the diameter of the egg, and do not diifer in any 

 noticeable detail, except size, from the eggs of Phyllopliaga. 



THE WHIT,E GRUB. OR LARVAL STAGE. 



The larval stage requires, from our figures, an average duration 

 of 2681/1. days (or about 9 months). The maximum duration, ob- 

 tained by adding together the maximum lengths of the three instars, 

 was 284 days; the minimum, 252i,l> days. 



No larvae younger than the third instar are found in the fields 

 after the latter part of January ; no larvae of the first instar are 

 found after November. 



First Instar. — The average duration of this instar. from 30 grubs, 

 was found to be 30 days; the maximum, 391/-. days, the minimum. 

 21 I/O days. The measurements of the grub in this instar were not 

 obtained, but can be easily estimated from the size of the egg. 



Second Instar. — The average length, from records of 10 grubs, 

 was 4514 days; the maximum, 54 days; the minimum, 37 days. 

 The dimensions of the only second-instar grub measured were : length, 

 10 millimeters; width of head, 1.5 millimeters. 



Third Instar. — The length of the last instar, averaged from but 

 two grubs, was 194 days. One of these required 186i-l> days and 

 the other 197 days to reach the pupal stage. 



Of twenty grubs in this instar that were measured, varying from 

 16 to 22 millimeters in length, the average width of head was 2.63 

 millimeters. 



PUPA AND PRE-EMERGENCE OF ADULT, 



The length of the pupal stage has not been determined, but doulit- 

 less requires in the close neighborhood of 20 days. 



Pre-emergence in the Guanica district at least, where the adults 

 first appear in the fields in August, probablj^ requires a shorter time 

 tliaii in those species which issue during the cool winter months, and 

 wait until spring to emerge from the soil. 



165 



