THE MELON FLY IN HAWAII. 



37 



as 4 days, or as many as 17 days, even during the hottest Hawaiian 

 summer weather, when the average daily mean temperatures for the 

 developmental period range between 78.2° and 79.3° F. 



Both temperature and the nature of the host fruit affect larval 

 development. Thus while 1 larva reached maturity and pupated in 

 4 days in fresh ripe papaya at 78.2° F., 2 larvae required 10 and 13 

 days, respectively, to reach maturity in a ripe Bartlett pear at about 

 79° F. The larvae developing in cantaloupes Nos. 1 and 2, recorded 

 in Table VI, hatched from eggs deposited during a period of 1-J hours 

 while the fruits were confined in a jar with adult melon flies, yet the 

 larval period in one fruit ranged from 7 to 17 days. 



Larval life may be extended through the medium of natural 

 barriers to the exit of full-grown larvae, within favored host fruits, 

 which prevent ready access to the soil, since in small partially dried 



Fig. 9. — The melon fly : Posterior spiracles of third-instar larva. Enlarged. 



(Original.) 



pumpkins, the interior of which is honeycombed by larval channels, 

 the epidermis has become too toughened to permit free larval exit 

 except at one or two places, and larval life thus may be appreciably 

 prolonged. In very moist fruits, such as the ripe tomato, no such 

 barrier to emergence is offered. While larvae feed best in partial 

 decay resulting from their own feeding, decays clue to the work of 

 bacteria or fungi, especially when they become acid, are detrimental 

 to larval growth. These varying factors, which influence either the 

 development of the larva or the time when it succeeds in forming its 

 puparium, make data unaccompanied by notes on temperature and 

 the condition of the host fruit of less value. 



Cantaloupes Nos, 1 and 2, the Bartlett pear, and the cucumber, re- 

 corded as hosts in Table VI, were sufficiently ripe for table purposes 

 when exposed for oviposition. Larvae placed in sound green but well- 



