101 



produces diuretic effects, a general stimulation of the circulation 

 and finally intense itching; larger doses produce considerable 

 giddiness, spasmodic contraction of the larynx, palpitation of con- 

 siderable violence and tetanic spasm of the trunk and limbs. 



The Melon Fly 



ITS CONTROL IN HAWAII BY A PARASITE 

 INTRODUCED FROM INDIA. 



By David T. Fullaway, Entomologist. 



(PVom Report of the Proceedings of the Third Entomological Meeting, 

 held at Pusa, India, February, 1918.) 



The Hawaiian Islands are situated in the midst of a vast ocean. 

 They are completely isolated from the continent, so that insects 

 detrimental to agriculture cannot easily reach them. But with 

 the development of trade on the Pacific, the Islands have be- 

 come a commercial crossroads, a day seldom passes without a 

 steamer putting into our main port, and despite the strict in- 

 spection and quarantine of horticultural products a serious pest 

 now and then does slip in. Our equable climate permitting al- 

 most continuous breeding, an excessive multiplication and rapid 

 spread of the pest soon result. Thus it was that the melon-fly 

 (Bactrocera cncurhitae) gained access to the islands about 189.S, 

 and thereafter melons of any sort could not be grown success- 

 fully. A somewhat similar experience later with a more destruc- 

 tive insect, the ^Mediterranean fruit-fly, aroused public interest 

 to the extent of inducing the Government to experiment' with the 

 possibility of controlling the injuriousness of the fly by search- 

 ing out and introducing its parasites, that is to say, other insects 

 that were known or could be ascertained to live at the expense 

 of the first. Parasitism among insects is a very common phe- 

 nomenon, which even the layman today is acquainted with, and 

 the check which this parasitism exerts on the multiplication of 

 insects is also well known. It should be pointed out here that 

 the same circumstances which prevent the migration of injurious 

 insects to our isolated islands, also prevent beneficial insects from 

 reaching us. Likewise, the same causes which lead to the 

 rapid spread and excessive multiplication of injurious intro- 

 ductions operate equally on the beneficial ones that prey upon 

 them. In other words, the method of controlling injurious im- 

 migrant insects by the introduction of their parasites is particu- 

 larly applicable to Hawaiian conditions. The experiment that 

 was tried with the Mediterranean fruit-fly was successful to a very 



