December, '14] SWEZEY: SUGAR CANE WEEVIL PARASITE 457 



After about six months the Tachinids were found estabhshed and 

 increasing in those plantations where the first liberations were made; 

 and in the course of about a year they were spread to all parts of these 

 plantations, in some instances covering an area five miles or more 

 across. 



NoAv, after three years, they are established almost entirely through- 

 out the sugar cane districts of the Islands. In those plantations where 

 the borers previously caused the greatest loss 'of cane, httle damage is 

 now occasioned, and there has been a saving of many thousands of 

 dollars to them. An indication of the beneficial reduction of the 

 borers by this Tachinid may be gained by these comparative figures 

 from one of the larger plantations where they have for a number of 

 years practiced the collection of the adult borers from the cane fields. 

 The past year 3,440 ounces of these beetles Avere brought in by the 

 collectors; whereas, the previous year 27,010 6unces were collected, 

 a reduction of over 87 per cent. Hardly an injured cane Avas to be 

 found in some fields harvested this year, of the same plantation, where 

 formerly a great deal of cane was lost by borers. 



In another plantation formerly suffering severely from borer attack, 

 there was a reduction of 44 per cent in the amount of damaged cane in 

 the crop harvested the second year after the establishment of the Tach- 

 inid. In most places, examination shows a parasitization of from 50 

 to 80 per cent. Oftentimes it is difficult to find a borer that is not 

 parasitized. 



The method of attacking its host is quite unique in this Tachinid. 

 The adult female deposits her eggs at openings in the rind of the cane 

 where the borer larvae feeding inside have come to the surface and made 

 tiny holes. Frequently small maggots are deposited instead of eggs. 

 The maggots search out the borer larvae in the channels where they are 

 feeding, penetrate the body and feed upon the juices and fat, eventually 

 killing the host when it is about ready to pupate after having con- 

 structed its cocoon of wound-up cane fibers. From one to a dozen 

 maggots may thrive in one borer larva, one, however, is sufficient to 

 kill the latter. Having become full-grown, the maggots emerge from 

 the empty skin of the host and form their puparia within its fibrous 

 cocoon. Two weeks are spent in the pupal stage, and when the adult 

 flies emerge they make their way out of the cocoon and from the cane 

 through the hole which the borer larva, before constructing its cocoon, 

 has instinctively made to allow for the escape of the adult borer when 

 matured. 



This is only a very brief account, but full details of the discovery, 

 introduction, establishment and life history of this Tachinid will be 

 given in a forthcoming Bulletin from the Hawaiian Sugar Planters' 

 Experiment Station. 



