DANAtDM. 1 13 



round the first segment of the abdomen. The abdominal 

 portion is the thickest, the segments being drawn so closely 

 together that this part of the pupa is less than one-half the 

 length of the thoracic portion. Colour clear pale green, with 

 markings of golden and ivory black. (Riley.) 



These particulars respecting the larva and pupa are obtained 

 from an article by Professor C. V. Riley in the Report of the 

 Missouri State Entomological Department for 1871. He says 

 that in that part of North America the insect is double- 

 brooded, the butterflies emerging in Jane and July, and 

 again in September and October, in plenty, flying until late 

 in the autumn, and the females hybernating, and laying 

 their eggs in the spring. He says that the larva has a most 

 nauseous scent, and that poultry will not eat it. Birds have 

 been seen to catch, and immediately drop, the butterfly. The 

 larva feeds freely upon Asclcpias tuhcrosa, A. curassavica, 

 A. cornuti, and A. 2^UT2mrcsccn^, but obstinately refuses 

 A. phi/tolaccoiJcs ; yet is said to eat Apomjnum. He further 

 says that it occurs commonly all over America, from Canada to 

 the Amazons, and occasionally appears in great multitudes ; 

 indeed that this is the case, almost every year, in some part 

 of the West. This occurs, generally, in the second brood, in 

 September or October, and there are records of flights in 

 such masses as to obscure the sun. 



One result, apparently, of this tendency to multiply into 

 vast numbers has been a stimulus to migration. Mr. W. L. 

 Distant, in the Tranmctions of the Entomological Societi/ of 

 London for 1877, draws attention to the fact that it had then, 

 quite recently, spread from America over many of the islands 

 of the Pacific, to Queensland and New Guinea, and on the 

 other hand had reached the Azores ; and he enters rather fully 

 into the possible means of its dispersal. He also refers to a 

 paper by a German writer showing that it had reached 

 Celebes. Lieut. Walker adds New Zealand, Norfolk Island, 

 and Tasmania, and, in a letter just received, Amboyna and 

 Ternate. 



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