6 BULLETIN 1081, U. S. DEPARTMENT .OF AGRICULTURE. 
ever eating when food is placed at their disposal. Others will eat 
only when food is placed directly in front of them or when they hap- 
pen to walk into it. When they have once tasted the sweets they will 
feed until the body is well distended. The best results were obtained 
by placing drops of brown-sugar sirup on the net or screen covering 
of the cages. In the large cages it was sprayed with an atomizer on 
the under side of the leaves of the tree. The flies have a liking- for 
the pulp of ripe papayas and also eat bananas but will not eat the 
juice of oranges. 
The following figures show the length of life of some of the flies : 
Fifty-four flies confined without food after emerging lived from 1.5 to 5.5 
days, with an average of 3.45 days. 
Thirty-six flies given water only lived from 3 to 6 days with an average of 
4.6 days. 
Seventy-six flies fed on sugar sirup lived from 3 to 31 days with an average 
of 7.4 days. 
Under natural conditions these figures probably do not vary much. 
Five to seven days represent an average life for the adult. 
COPULATION. 
The insects copulate usually on the leaves or fruits of the papayas, 
but can only rarely be observed. Copulation takes place during the 
daytime, for the male is more active then, as noted above, He seems 
to experience some difficulty in holding the female in position because 
of the long ovipositor. To accomplish his object, he alights on top 
of the female and, clasping her body with the first two pairs of legs, 
he draws the ovipositor back and up with the remaining pair. Then 
by practically standing on his head he is able to bring the tip of his 
abdomen in conjunction with the end of the ovipositor. They usu- 
ally hold this position for several minutes or longer, one pair being 
observed to remain for nearly two hours. If disturbed the female 
will walk around the fruit or even fly to another tree, always carry- 
ing the male along in position. In captivity the flies very seldom 
copulate. This is true when confined in the large cages over the trees 
(PL II, at left) as well as in small cages or jars in the laboratory. Of 
several hundred adults bred out in jars and observed at all hours of 
day and night, only a very few ever made any attempts at copulation. 
These cases happened when the flies were 4 or 5 days old and had been 
fed on sugar sirup or fruit pulp. If given no food they soon die 
without mating. 
OVIPOSITION. 
Oviposition usually takes place in the evening, that being the 
time the adult females are most active. It has been observed 
occasionally, however, to take place at all other times of the day. 
The fruits selected by the females in which to lay their eggs are 
