sum of the averages of the egg. pupa and separate instars of the 

 grul). aniounted to 268\-> days, witli a inaxinium of 336 days and a 

 miniinum of 207 days. Reduced to mouths, this gives an average 

 duration of 9 nine mouths, a maximum of approximately 11 months, 

 and a minimum of 7 months. 



It is notable with regard to the life-cycle of this species that no 

 eggs were laid by adults in confinement later than the middle of 

 May, and that all but nine of the total number of eggs were laid in 

 March and April. Tliis shows that individuals recjuiring the shorter 

 length of time to pass the immature stages would reach the adult 

 stage during the winter months, and would therefore pass the remain- 

 ing time in the soil as adults until the regular time of emergence 

 (in the latter part of February and March). Those requiring the 

 maximum of eleven months (which w'ould be very few), even though 

 coming from eggs laid in May, would still reach the adult stage th'? 

 following April, in sufficient time to mate and laj' eggs by ]May again. 

 This may account for the species having but one brood, appearing 

 Avholly between February and June. 



The Egg Stage. 



The egg of this species does not noticeably differ from that of 

 P. vandinei except in being smaller. When first laid it is slender, 

 oblong-oval, about 2 mm. in length by 1.2 mm. in breadth, and opaque 

 pearly white in color. At the end of ten days it is greatly swollen 

 and less opaque in color : it becomes nearly spherical, being then 

 about 2.4 mm. in length bj^ 2.2 mm. in diameter. Just before hatch- 

 ing, the brown mandibles and the segmentation of the young grul) 

 become plainly visil)le through the shell of the egg. 



The duration of the egg stage, from an average of 505 eggs whose 

 hatching was observed in confinement, amounted to 131/2 days. The 

 maximum duration was 19 days; the mininuim, 11 days. 



The White-Grub, or Larv.\l Stage. 



As in other May-beetles, the larval period of this species includes 

 four distinct stages: the first, second and third instars, and the pre- 

 pupal stage. Between the first and second instars, and again between 

 the second and third instars, there is a molt of the larval skin, follow- 

 ing which the head and legs of the grub increase very perceptibly in 

 size. At the end of the pre-pupal stage there is also a molt, to form 

 the pupa. There is no molt between tlie Inst instar of the grub and 

 the pre-pupal stage, and the change from one condition to the other 

 is quite gradual. This change in condition does not take place until 



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