PHYCIODES I., II. 



Tharos which appeal- at Coalburgh, as I have stated), and that if the summer 

 was lengthened by a month or two, these could lay the foundation of another 

 summer generation. 



The experiments related led me to try the effect of cold on chrysalids of the 

 forms Walshii and Telamonides of Papilio Ajax, in 1875 and 1876. These are 

 both winter forms, and from their chrysalids either the summer form IfarceUus 

 would have issued in a few days, or in case any chrysalis passed the winter, as 

 happens to some extent in every brood of this species, either Walshii or Tela- 

 monides would have issued the next spring. The result was that a large propor- 

 tion of the chrysalids subjected to cold yielded butterflies the same season, and 

 nearly all these were changed to the winter form Telamonides. Where the cold 

 was continuous (about 40°), the change was complete ; where it was insufiicient 

 and intermittent, the change was partial, individual butterflies blending pecu- 

 liarities of the summer and l)oth the winter forms. 



The experiments made on Tharos, in 1876, I have stated. The following year 

 I brought to Coalburgh, from the Catskills, eggs obtained from 3Iarcia. The 

 chrysalids therefrom I placed in an ice-chest, at intervals of from ten minutes to 

 some hours after they were formed. For twenty days they were subjected to a 

 temjjerature of 33° Far., when all were removed. They were divided into three 

 lots, the first containing all which were exposed to cold at from one to nine hour's 

 after forming, the second at from thirty to sixty minutes, and the third at from 

 ten to twenty minutes. But I afterwards discovered that in this last lot were 

 three chrysalids which were two days old before exposure. The butterflies 

 began to emerge on the seventh day, and by the ninth all had emerged that 

 were alive. Of the first lot (exj^osure one to nine hours after forming), there 

 emerged nine butterflies, 5(? 49. The males were Marcia, D, and, though vary- 

 ing much on tlieir under surfaces, were all like examples of Marcia taken in the 

 Catskills. Of the females, two were good examples of Marcia, C, but the other 

 two were suffused, the colors having run together, so that the definite markings 

 of the species were lost; also the upper surfiices were more or less hoary. (Figs. 

 9, 10.) Of the second lot (exposure thirty to sixty minutes), emerged five fe- 

 males, no males. Three were very little if at all changed, but the other two 

 were suffused, though to a less degree than those before mentioned. (Figs. 7, 8, 

 9.) Of the third lot (exposure ten to thirty minutes, but with three chrysalids at 

 two days), there emerged two females only. One of these was not distinguish- 

 al:)le from the summer form, but the other was a fine example of Marcia B, the 

 under side of the hind wings being largely melanized. 



Figs. 11, 12, represent the butterfly described by Mr. Saunders as Melitxea 

 Packardii ; but it is evidently a suffused Tharos, of the same character as those 



