502 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



By the middle of September all but 53 had emerged. These 53 pupse 

 were brought to Washington and from them butterflies continued 

 to emerge at irregular intervals all through the winter and spring, 

 sometimes two or three a day. The last to emerge did so some time 

 subsequent to July 7, on which date I left Washington. Thus from 

 the same lot of pupce dating from the middle of August, butterflies 

 emerged continually up to the end of the first week in the following 

 July, for very nearly 11 months, the chrysalids having all been kept 

 in the same box in a heated house. Only one chrysalis died, and that 

 was less than half the normal size. 



In the summer of 1924 the caterpillars were very scarce. Fifteen 

 secured in Essex, Mass., pupated on and about September 1. These 

 were brought to AVashington about the middle of the month, and the 

 butterflies emerged at irregular intervals from December to April. 

 The last failed to spread its wings, the one preceding did not spread 

 its wings completely, and one has not as yet (May) appeared. 



All of the butterflies Avhich emerged in Washington differ from 

 those caught or raised in Massachusetts in having the black mark- 

 ings on the forewings more restricted, presumably through the pupae 

 having been kept at a temperature above the normal for them. 



Food of the caterpillars. — The large white woolly aphis of the 

 alder {Schizoneura tessellata)^ which forms conspicuous snowy 

 colonies, seems to be the chief and favorite food of the caterpillars 

 of this little butterfly. But it has several times been found among 

 the colonies of another aphis {Peiriphigus ivihricatus) on the beech, 

 and in the leaf curls of a related species {P. fraxvnifolii) on the ash. 

 My older son found five in a colony of w^oolly aphids {Meopro- 

 ciphilus attemiatus) on the carrion flower {Suvilax herhacea) near a 

 heavily infested alder thicket. 



The caterpillars and the pupje have been found on various plants, 

 such as witch-hazel ; but there is no certain evidence that normally 

 they live on these. 



In captivity the caterpillars will eat other kinds of aphids. Miss 

 Morton found that they would eat the red aphids on wild cherry. 

 Mr. Edwards put some aphids which he found on weeping willow in 

 a tube with some j'^oung caterpillars. He watched for some time, 

 but there was no haste on the part of the caterpillars. He saw one 

 of them go to an aphid, nose at it, push it, and bite at it, lifting it 

 partly off the leaf (the aphid being the larger of the two) and shak- 

 ing it as a dog would shake a rat. But the victim escaped and re- 

 treated to the reverse side of the leaf and the larva rested. Next 

 morning not an aphid was to be found. He obtained another small 

 supply of willow aphids and presently saw a caterpillar bite one 

 near the head and cat into the body so that its own head was buried, 

 tho aphid not resisting, not even removing its beak from the leaf. 



