46 BULLETIN 491, U. S. DEPARTMENT OF AGRICULTURE. 



parasite (Spalangia hirta Haliclay) from 500 puparia of the melon 

 fly, both he and the writers appreciate that this parasite is of no 

 value at present as a control agent, and, for all practical purposes, 

 can not be considered a factor in repression. Although the writers 

 have reared adult flies from many thousands of larvae, they have never 

 reared a parasite during a period of 3 years. This is true, notwith- 

 standing the fact that melon-fly pupae have been used experimentally 

 (39) in the laboratory for rearing the Mediterranean fruit-fly 

 parasites, Opius hwnilis Silv. and Diachasma tryoni Cam. Five 

 thousand pupae of the melon fly, secured from Chinese cucumbers 

 (Momordica sp.) growing wild near coffee fields in the Ivona district, 

 Hawaii, during 1914 and 1915, produced no parasites, although the 

 pupae of the Mediterranean fruit fly secured from the coffee cherries 

 showed a parasitism ranging from 85 to 98 per cent. 



The great need for methods of natural control has been appre- 

 ciated, and the Hawaiian Board of Agriculture and Forestry em- 

 ployed Mr. D. T. Fullaway to search for and introduce parasites 

 of the melon fly to Hawaii from the Indo-Malayan region. 

 Mr. Fullaway has returned to Honolulu after travel in India and 

 the Philippines, but the results of his investigation have not yet 

 been made ready for publication. It may be stated, however, that 

 he has introduced an opiine parasite, which gives promise at the 

 present time (June, 1916) of becoming successfully established in 

 the Hawaiian Islands. 



The mortality among the eggs and larvae noted occurs chiefly in 

 rapidly-growing cucurbits, particularly during the cooler seasons, 

 when climatic conditions arrest fly development, but not to the same 

 degree as that of the host, and to a less degree in much older fruits 

 during the warmer seasons. Death among eggs and the young larvae 

 follows the development of a gall-like hardening about the egg 

 cavity, and on occasion about the newly made burrow of the first- 

 stage larva. This gall-like formation develops rapidly, particularly 

 in such hosts as the gourd and watermelon. While both of these 

 hosts are very susceptible to repeated attacks, individual fruits often 

 succeed astonishingly well in throwing off fatal attack by such 

 formations as that illustrated in Plate XXI, figure 1. The writers 

 have seen large gourds used for household purposes by the poorer 

 population which on the outer side of the rind showed the open breaks 

 made by many colonies of eggs and young larvae, while the inside 

 showed all ruptures of the epidermis to be sealed by a hard gall, 

 variously formed by the proliferation of plant tissue. The follow- 

 ing data resulting from the examination of a young watermelon 3 

 inches in diameter on April 19, 2 days after it was gathered from 

 the field, will serve as a fair example to illustrate this mortality 

 and are representative of other data on file. 



