i85 



forms and their sequence were the result of his observations in the 

 field. " It is the opinion of Mr. Boll that the eggs laid in June do not 

 develop, owing to lack of food, till the summer is past." He had be- 

 fore said that the food plant, Buffalo Clover, dies off before the last 

 June butterflies appear, and does not revive again till the advent of 

 the November rains, so that there was absolutely nothing for the 

 young larvai to feed upon. And I remarked on this: " I apprehend, 

 if there is any retardation, it must be with the larva?." Now, Mr. 

 Boll never had obtained an egg from the female of form Eurytherne 

 or he would not have conjectured that the egg is retarded from June 

 to October. He would have known whether it hatched or not. In 

 fact, the egg must hatch in three or four days, and the young larva 

 must go into lethargy at the root of the plant, under the surface of the 

 ground, to come up when the rains fall and the clover begins to grow. 

 Mr. Wright,of San Bernardino, where there is a dry season as in Texas, 

 when green vegetation totally perishes, observed an Argynnis Coro- 

 nis on the ground depositing eggs on the crown of a violet plant (dead 

 at top, of course), under the surface. He sent me the eggs, and they 

 hatched at Coalburgh in the time usual with eggs of the larger. 

 Argynnids, and the larvre went at once into lethargy. In cold 

 weather, or by cold applied, the hatching of butterfly eggs is retarded, 

 but heat has the opposite effect. This shows that Mr. Boll never bred 

 from egg of Eurytherne. He saw a regular series of butterflies, increas- 

 ing, as he says, in size, extent, and intensity of orange as the season 

 progressed. From caterpillars found on the clover, he got what he 

 calls Chrysotheinc [Keeicuiydin or Ariadne, it is not certain which), 

 and in letter to me, but not in his published paper, he says these cater- 

 pillars looked exactly like other caterpillars which produced Eury- 

 therne, and these also had been fou id on the clover. He sent me a large 

 invoice of his captures of butterflies, indicating the date at which each 

 one was taken, and I showed him that certain ones were Ariadne, cer- 

 tain ones Keewaydin. and certain ones intergrades. 



So I come back to my first statement, that Mr. Boll did not "breed 

 Eurytherne and its related forms " in 1874, '75, or at any time, and so 

 "give the first step to a better knowledge, and to a scientific reduction 

 of the species of Colias ;'' nor did he " prove that all three (forms) 

 belong to the same species." He surmised it. Messrs. Bean and 

 Dodge and myself proved it, not from field observations only, but 

 actual breeding from eggs laid by females of the different forms found 

 in Illinois and Nebraska. The eggs were obtained expressly to find 

 out the connection, and it was found by us and no other person. The 

 relation of the Texas Ariadne, which is not found in Illinois, we had 

 to infer from analogy, and from Boll's field observations. 



