Pitner gasoline lamp, with a view of finding some suitable method of 

 taking advantage of this fact for the destruction of the beetles. Th(> 

 lamp was T^laced on the roof of a two-story building near the insee-. 

 tary at Santa Rita, and a canvas stretched on a vertical frame was 

 put beneath the light. Since a few individuals often come to an 

 ordinary lamp in a room, it was expected that the Pitner light, with 

 its great power, would attract large numbers. This hope was not 

 justified, as out of tAventy-three evenings in July, August, October, 

 and November during which the light was run, beetles were taken 

 on only seven, a total of twenty-four being taken. 



The reason for this scarcity of beetles was that the Pitner light 

 was always started about 8 o'clock, and PhyUophaga adults are ordi- 

 narily only attracted to light during their flight and before they 

 have settled on foliage to feed (before 7:30 p. m.). To have any 

 practical efificiency in attracting vandinci adults for destruction, a 

 light nmst be close to the ground, and must be started immediately 

 at dusk, while beetles are flying. It need not be run for over an 

 hour after dark, as time after that is wasted. There have been cases 

 where adults of this species and portoricensis have left their feeding 

 on the foliage and flown to a motorcycle headlight as late as midnight 

 or after, but these cases are rare. Almost never, while collecting 

 beetles with a bull's-eye light, have they been known to leave their 

 feeding and fly to the light. 



COPULATION. 



This species is not often found in copulation in the field, the 

 reason being that collecting is usually done after 8 p. m., while 

 mating takes place before that hour. On one occasion recorded, when 

 collecting was done between 6:45 and 8:25 p. m. (on October 14), 

 out of 79 adults collected on cane, "salcilla" and "malo.iillo," only 

 one pair was found in copula (at 7 p. m.). Lateness of the season 

 may have accounted for so few being found copulating at that liour. 



Pairs were occasionally found copulating on the foliage of small 

 casuarina tress near the insectary. Pairs thus observed on two ev(m- 

 ings in April were recorded as follows : 



(1) Copulation began before 7:30; ended at 7:45; duration 15 minutes -|-> 



(2) Copulation began before 7:30; ended at 7:53; duration 23 minutes -)-. 



(3) Copulation began before 7:35; ended at 7:45; duration 10 minutes 4-- 



(4) Copulation began before 7:35; ended at 7:48; duration 13 minutes -f. 



(5) Copulation began befoi-e 7:35; ended at 7:50; duration 15 minutes +. 



(6) Copulation began before 7:35; ended at 7:50; duration ]5 minutes +. 



(7) Copulation began at 7:33; ended at 7:52; duration 21 minutes. 

 (S) Copulation began at 7:34; ended at 7:53; duration 19 minutes. 



81 



