the largest recorded number of these grubs was taken from a plowed 

 cane field (tablou 21, hacienda Santa Maria, Feb. 25, 1915), actual 

 count of a pailfull of grubs gave the following results: Phytalus 

 insularis (all 8d instar), 88: PhjjlJopliaga vdiidiuei (2d and 3d in- 

 star), 970. 



The Beetle. 



The adult is dark, burnished l)rowu with somewhat lighter mar- 

 gins, more noticeable on the thorax. The length varies from 9yo to 

 llVi' millimeters, the breadth about half of that. 



While not belonging to the genus PhyUophaga, this insect can very 

 rightly be considered a May-beetle, because of its very close relation- 

 ship to that genus in every particular. In fact, some of the charac- 

 teristics upon which the genus is founded are so unstable as to cause 

 some specialists to question whether the genus name should be re- 

 tained. In the writer's oi)inion the genus is a valid one, because of 

 the marked characters of genitalia, distinguishing it from Phyllophaga. 



Life-History. 



The life-cycle of this species, like the four preceding, covers just 

 one year. In confinement, no grubs were successfully reared to ma- 

 turitj^ in the smaller boxes, but in a large outdoor cage a large number 

 came through from egg to adult. The eggs from which these came 

 were laid between August 25 and September 25, and the first adults 

 of the new generation were observed in the cage on August 20 of 

 the following year, clearly proving the life-cycle to be one year. 



Unfortunately, the soil in this cage was not dug up and examined 

 at the right time of year to find pupae, and preserve specimens of 

 them. The pupa of this beetle is still unknown. On January 19. 

 a part of the soil in the cage Avas examined, and 60 grubs were found, 

 of which 57 were in the flnrd instar and 8 at the end of the second 

 instar. On April 80 all tlie soil was examined, and 134 grubs found, 

 all of which wei-c in the third instar, 2 of them dead and covered 

 with Metarrhizium spores. No pupae wci-c present at that date. 



In the tin boxes, two gi-nbs reached the ])rc-pupal stage, but \)<)\h 

 failed to pupate. From them, howcvei-. Ihc length of tlie third instar 

 was ascertained. 



If we may estimate the pupal stage of this species as reciuiring 

 20 days, adding to this the averages for the other stages and instars, 

 the average duration of egg-to-adult pciiod is found to lie 801 ;lays 

 (the same as for the sugar-cane white-grul)) ; the maxiuunn. 816 days; 

 the minimum, 283 days. 



164 



