150 THE CANADIAN ENTOMOLOGIST. 



but walked past and back and forth and was on both sides of the leaf 

 The ants were somewhat inquisitive but did not trouble the larva, nor 

 were they disturbed by it. This went on for ^bout" 15 minutes, when I 

 removed the larva. 



I put the next sized larva (2nd moult) on same leaves, and the ants 

 were agitated, ran about gesticulating, but paid more attention to 

 their cows than to the larva. I put this larva on a plum leaf by a large 

 colony of aphides, at which were a dozen of the black ants. The ants 

 sprang at it, bit at it everywhere, especially trying to get a hold under the 

 edge of the body, where the surface is naked, or at the joints of the seg- 

 ments, or at 2, which being bent over the head is more exposed than any 

 other segment. One determined fellow seized on 2 and was hardly to be 

 dislodged, was at last by violent jerking of the head, but wounded the 

 larva so that blood flowed. When the attack was at the joints the larva 

 squirmed so as to tighten the joints just there. These attacks were sim- 

 ultaneous and by at least six ants at a time. The larva crawled away and 

 the assailants mostly dropped off I though it best to come to the rescue, 

 else I should lose the larva. 



I then put the largest larva (3rd moult) amongst the same excited ants, 

 and they attacked it in same manner, but seemed unable to make impres- 

 ^sion on it. The hairs protected the whole upper side more sufiiciently. 

 The larva crawled up and down and over the leaf, followed by some of 

 the ants, who attempted to seize it at every vulnerable part. But no harm 

 was done. I repeated the experiments the next day, and came to the con- 

 clusion that the willow ants were mild-tempered, and seemed unhkely to 

 hurt a larva ; but that the black ones were fierce and would attack wher- 

 ever they saw their enemy. 



Now it may be that the butterfly avoids the fiercer ants and the 

 aphides they guard, and therefore that the larvae are not to be looked for 

 on certain plants. There is room for farther observation on this point. 



I had noticed that whenever one of these larvae was removed by forceps 

 a thread held it to the object, and I watched when making the experi- 

 ments related to see if the ants would force the larvae to drop from the 

 leaf. But they did not drop. I shook the largest larva out of the box 

 till it let out a thread a length of four inches. Then held the box to see 

 if the larva would climb the thread, which it did, in about 20 minutes. 

 It twisted its body into a spiral and whirled about so fast that I could 

 not bring the lens to bear, but I could see that jaws and feet were active, 



