CARNIVOEOUS BUTTERFLIES — CLARK 503 



After a monient the caterpillar let go and went its v. ay. Not find- 

 ing more aphids on Tsillow, he searched many trees and shrubs in 

 vain, but at last he found a young wild-plum somewhat infested 

 with them and thereafter had a moderate supply. 



Relationships with ants. — Miss Morton noted that there are four 

 species of ants guarding the aphids on the alders, and she found 

 fewest caterpillars among those guarded by a large kind with black 

 head and abdomen and red thorax which swarms all over them for 

 the sake of the exceedingly sweet liquid they exude. The ants do 

 not let the caterpillars alone, biting at them furiously whenever 

 they see them; but until nearly fully grown the larva) lie concealed 

 under the aphids with a web covering them and can not be reached 

 without disturbing the aphids. 



One morning she found what she thought was a full-grown larva. 

 It was resting in a fork of the bush close to a large colony of the 

 aphids; but while she was wondering how she should get it in her 

 box the way Avas suddenly made plain by a large ant rushing at it 

 and biting it furiously. 



Once she came across a place where the large black and red ants 

 were in a state of great excitement, running and biting in every di- 

 rection, and had probably just discovered and routed a full-grown 

 larva, as a large brown spot with all the aphids cleared off showed 

 itself on the limb. I believe that this interpretation is not quite cor- 

 rect. It is more likely that the brown spot represented the previous 

 location of a fully grown larva which had finished feeding and 

 dropped to the ground to pupate, and that tlie ants were annoyed at 

 the discovery of the gap in the aphid colony. 



Mr. Scudder stocked with aphids an alder he had planted for the 

 purpose in his garden, and on July 31 placed there a caterpillar in 

 the second stage. The aphids were all small, and in two large clus- 

 ters. The caterpillar moved about over the lower colony for an hour 

 or more, apparently looking for a good place to push under it, and 

 he observed its contact with the ants on 20 or 30 occasions. They 

 tickled it with their antenna) and it remnined at such times abso- 

 lutely quiet, generally moving off Avhen they left in the opposite 

 direction to that in which it had been touched. They offered it no 

 further attack. Having to leave for an hour, he found on his return, 

 just at nightfall, that the caterpillar had quitted the lower colony 

 for the upper, 6 to 8 inches distant up the stem, and the same process 

 Avas repeating with the ants there. Tlie next morning it was found 

 dead beside the colony, the outer edge of which it had eaten and 

 removed, its body bitten just in front of the middle on each side in 

 two or three places. The colony was composed of individuals too 

 young to burrow under, and being unable to conceal itself it had 

 fallen victim to the ants, then victoriously nursing their colony. 



