Ch. VII.] THE HELICOXIDJE. 109 



their instinct taught them to avoid it, for, although 

 startled, they threaded their way through open spaces 

 and between the webs with the greatest ease. It was 

 one instance of many I have noticed of the strong 

 instinct implanted in insects to avoid their natural 

 enemies. I shall mention two others. The Heliconidce, 

 a tribe of butterflies peculiar to tropical America, with 

 long, narrow, weak wings, are distasteful to most ani- 

 mals : I have seen even spiders drop them out of their 

 webs again ; and small monkeys, which are extremely 

 fond of insects, will not eat them, as I have proved 

 over and over again. Probably, in consequence of this 

 special protection, they have not needed stronger wings, 

 and hence their weak flight. They are also very bold, 

 allowing one to walk close up to flowers on which they 

 alight. There is one genus with transparent wings that 

 frequents the white-flowered shrubs in the clearing, and 

 I have sometimes advanced my hand within six inches 

 of them without frightening them. There is, however, 

 a yellow and black banded wasp that catches them to 

 store his nest with ; and whenever one of these came 

 about, they would rise fluttering in the air, where they 

 were safe, as I never saw the wasp attack them on the 

 wing. It would hawk round the groups of shrubs, trying 

 to pounce on one unawares ; but their natural dread of 

 this foe made it rather difficult to do so. When it did 

 catch one, it would quietly bite off its wings, roll it up 

 into a ball, and fly off with it. Again, the cockroaches 

 that infest the houses of the tropics are very wary, as 

 they have numerous enemies birds, rats, scorpions, and 

 spiders : their long, trembling antennae are ever stretched 

 out, vibrating as if feeling the very texture of the air 



