396 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



strong enough colony established that they may continue in spite of 

 the loss. A brief discussion of these enemies may not be out of place 

 here. 



Before the flies escape from the cocoon of the beetle, many of them 

 will be destroyed by rats. These rodents are particularly abundant 

 in some fields and especially so under the moist climate conditions 

 about Nausori. There I found many of the borer cocoons had been 

 torn open by the rats in their search after the borer grubs. This loss 

 will not be of any importance, however, after the flies become once 

 estal)lished. 



I should place the small brown ant {Fheidole megacephala) at the 

 head of the list of mortal enemies of the flies. This is one case where 

 his great industry will not be appreciated. At every stage of our 

 breeding work we had to contend with these insects. They were on 

 the ground about the cages in myriads; at the least opportunitj' they 

 swarmed inside, if a mere thread was blown on to the protective water 

 basins, we found that they had moved in their whole household by 

 morning. We used carbon-bisulphide most effectively in such cases. 

 We often noticed the adult flies attacked in the field soon after they 

 emerged. Even a single ant, when he sets his jaw like a bull dog upon 

 the fly's leg, seems to render it helpless, at this time. Often upon the 

 stalk where the flies are emerging, we find a swarm of ants. 



It is only because the borers plug the channel behind them and 

 build an ant-proof cocoon, that the maggots are saved from destruction. 

 The ants, even make short work of the borer itself, if it fails to take 

 these precautions. Many tim.es we had the ants get into our vials and 

 bite holes in the grubs, even carrying them off piecemeal. The pupa- 

 rium of the fly, is usually found inside the cocoon of the borer; but even 

 when free, in the borer channel, the ants appear unable to injure them. 



Everywhere in the cane we found spiders; a large jumping species 

 being most common. We did not see them in the act of springing upon 

 one of our flies, but they were observed feeding in this way upon some 

 of the other species of flies which are common in the cane field. These 

 spiders never build webs but hide away in the leaf-sheaths of the cane 

 and spring upon any unsuspecting insect that chances to alight near 

 them. The habit of the Tachinid flies of searching about over the 

 cane stalks renders them an easy prey to such attack. 



Lizards, too, were rather common in the cane. One species, with 

 feet fitted for an arboreal life, gave us considerable trouble by getting 

 into our cages. Each one captured, showed on dissection, that he had 

 his stomach filled with insects; but we never happened to find any 

 of the Tachinid flies. Undoubtedly, however, he would take them if 

 they chanced in his way, for he usually had several species of flies in 

 him. 



