October, '14] ILLINGWORTH: TACHINID PARASITES 397 



Dragon flies were very abundant in the field, especially during the 

 evening. We often observed them circling about our liberating boxes, 

 feecHng upon the smaller insects. Though their principal food con- 

 sists of flies, we never observed them in the act of catching one of the 

 Tachinids. 



Insectivorous birds appeared to be even a greater danger. Two 

 common species were observed with some care — a small fly catcher, and 

 a swallow. The first, flies in and out among the canes, and no doubt 

 does considerable good in checking the ravages of several cane pests. 

 His habits, nevertheless, render him a foe to the fly. The swallows 

 feed entirely on the wing, over the cane or in the open places. Their 

 beaks could be heard continually clipping together, registering the 

 number of insects that they were taking in their swift circling flight. 

 Probably the flies Avould receive little injury from them, except during 

 the mating flights of the Tachinids, when they buzz about over the cane. 

 Definite data on this subject could only be secured by making an ex- 

 amination of the stomach contents of a number of the birds that were 

 killed after they had been feeding for some time. 



There are a number of other organisms that are closely associated 

 with the developing flies in the field which may prove to be detrimental 

 to them. The earwigs that are ever present in the leaf-sheaths of the 

 cane, are known to be often predaceous upon other insects. Cock- 

 roaches, too, are to be found everywhere, and are omnivorous feeders. 

 The tunnels of the borer were often filled with mites. These attacked 

 the emerging beetles in great numbers and were often found on the 

 newly emerged flies. Whether or not any of these do serious injury to 

 the Tachinids, needs further investigation. 



Since the first flies were liberated during the latter part of July, it 

 is rather early at this ^ATiting — November 12th — to find the parasites 

 in the field. Though the flies were found to be established in Hawaii 

 in about three months after they were liberated, we do not expect to 

 discover any of the parasites in the field, in Fiji, until the cane is cut 

 in December. When the flies are actually found breeding outside, 

 the troublesome work with the cages can be discontinued. 



Bibliography 



The published notes on the breeding of these flies are principally 

 found in three papers in the Hawaiian Planters' Record by Mr. Fred- 

 erick Muir, as indicated below. In these papers Mr. Muir describes 

 the many experiences and hardships of his search for the parasites, 

 throughout the East Indies; and the final successful landing, in Hono- 

 lulu, of a good colony of adult flies and puparia; the results of which 

 have proved so beneficial to the sugar industry here. 



