crumpled molt skin (Plate III. fig. 9) remains near it, at the caudal 

 end. 



The average duration of the pupal stage, from 22 observations, 

 was 211/2 days; the maximum, 26 days; the minimum, 17 days. 



From thirteen measurements, the average length of the pupa was 

 25.1 mm., the average width 11.15 nun., and the average breadth of 

 the head 8.18 mm. 



A day or two before hatching into the adult, the pupa turns over 

 in its cell and lies with the back upward. In this position the adult 

 is always found in the cell, never with back downward. On a pupa 

 about to hatch the skin is wrinkled, and the white color of the elytra 

 may be seen througii elytral sheaths. (See Plate III, fig. 10.) The 

 formation and sculpture of the legs may also be seen through the 

 now transparent pupal skin. 



ISSUING AND EMERGENCE OF ADULT. 



An adult just issued has only the legs, head, and thorax brown 

 the elytra being white and soft, and the wings extended their full 

 length beneath the elytra. (See Plate IV, fig. 6.) In a few hours 

 the beetle turns tawny yellow in color, then gradually deepens in 

 shade during the following week. 



The term issuing applies to the breaking of the pupal skin, and 

 the exit of the newly formed adult from the pupa ; the term emer- 

 gence applies to the appearance of the beetle above ground. The 

 interim between these two periods is spoken of as the period of pre- 

 emergence, and is the time spent by the newly-hatched beetle in i\w 

 pupal cavity in the soil — a time very necessary for the chitinous 

 parts of the beetle to l)ecome perfectly hard, so that it can dig its 

 way upward to the surface of the ground. 



In many North American IMay-beetles the pre-emergenee of adults 

 covers a period of several months — usually from the late summer 

 or fall of one year to the spring of the next. In the Porto Rican 

 species this period extends rarely over five to six weeks, judging 

 from observations. 



Because of the fact that most of the confined specimens of van- 

 (liiiii were reared in small tin boxes, in which the adults at time of 

 pre-emergence were disturbed and did not behave normally, our rec- 

 ords of pre-emergence are somewhat incomplete. The following notes, 

 however, prove it to extend over a period of two weeks or more : 



(1) No. 547. — On July 1 two adults hatched from pupae in earth in a jar, 



77 



