COOL AIR EXPERMENTS WITH JUNONIA 



COENIA 



WILHELM SCHEADEB 



In my first artiolc on tcniperature experiments, pu1)Iishe(l in Volume IV, 

 No. 1 of this Journal, I ileseribed only breeding experiments at the warmth of 

 90 degrees, and as I fonnd that cool air has a very different influence on the 

 formation of the markings and color of tliis butterfly, I determined to give 

 these experiments a very carefid observation, and to repeat them several times, 

 to be sure that it is the cool temperature only, which produces these changes. 



In the fall of 1910 I took eighty-five young caterpillars from my thir- 

 teenth generation which were bred in 90 degrees damp air, and in darkness, 

 and raised these young caterpillars in a shady place, in an open shed, where 

 the lowest average temperature at night, for the first half of October, fell to 

 60 degrees and the highest average in the daytime from 11 to 9 o'clock was 

 about 75 dgrees. I obtained the first chrysalides on October 17th, and the first 

 butterflies, bred in the same temperature on October 2fith. In this part of the 

 thirteenth generation, I got a high percentage with double ocelli on the fore 

 wing; however, what was still more remarkable, all had both ocelli of the hind 

 wing greatly enlarged ; this was so much the more striking as in the previous 

 generations bred in a warm temperature, the ocelli of the hind wing became 

 slowly reduced in size, from one generation to another. This enlargement of 

 the spots was not the only result, as many developed new small ocelli, which 

 were between the large and small ones and .iust above the latter. This is 

 shown in Fig. 253, 1. The remainder of the ehry.salides from the caterpillars 

 raised in a cool temperature I bred in 90 degrees warm, damp air. and in 

 darkness: here also there was the same result, but there were not so many with 

 the new small ocelli, and the ground color was darker (Fig. 253, 2). In all 

 bred in a cool temperature the ground color is somewhat lighter near the bor- 

 der, and sliows generally a yellow band on the outerside of the ocelli of the 

 hind wing, the same as in our local form; the lighter ground color occurs in 

 all bred in cool temperature, in darkness as well as in the light. The under- 

 side also changes in color. In all .Tun/mia bred in warm, dry air, in darkness 

 or in light, the under side of the hind \\'ing is largely of a uniform gray, only 

 the middle field is somewhat darker: this gray color occurred always in the 

 twelve successive generations bi'od in a warm temperature : however, the thir- 

 teenth generation bred for the first time in a cool temperature shows the under 

 side of the hind wnng, and the tip of the fore wing a brownish-red color, with 

 the middle field somewhat violet: this color deepens with the fall in tempera- 

 ture, and the length of time tlie chr.vsalides are exposed to it. This change in 

 shade will easily account for the variously colored undersides of J. coenia in 

 our Eastern and iliddle "Western States, where it is cold enough to give the 

 chr.vsalides a long rest. 



