COLIAS IV. 



in the earlier stages, and in the later are often just as much alike. But many 

 larvse of the former have developed a second lateral band, making the species at 

 this stage polymorphic. The close resemblance extends also to eggs and chrysa- 

 lids. In the notes to Philodice, I have recorded instances of hybridism between 

 the two. The larval food plants are also the same. The larvte of Eivry theme 

 which I have received, and which were stated to have been fed on plants not 

 found here at Coalburgh, fed as readily on red clover as do the larva? of Pldlo- 

 dice. 



'Philodice is nowhere a polymorphic species, but everywhere a variable one. 

 Its varieties are not separable, but are so thoroughly intermingled that any fe- 

 male of any brood of the year may not unlikely discover in its j^i'ogeny the ex- 

 tremes and all shades of variation. 



And in the Rock}^ Mountains, and in the Mississippi Valley, where Eurytheme is 

 but two and three brooded, the two principal forms of the species are intermingled 

 as in Philodice. In these districts it is a variable species. But in Texas, where 

 the length of the warm season permits the species to become many brooded, it 

 is seasonally polymorphic. The explanation of this difference I conceive to be 

 this : at the north, more or less of the fall butterflies hybernate, as also do larvae 

 from eggs laid by some of the females of the fall brood, the latter producing 

 butterflies in the spring and while the hybernators are still flying. The series 

 begins, therefore, in the spring with all the forms or varieties of the butterfly 

 which are found in the district, and cross-breeding occurs then and all the season 

 through. But'in Texas, the butterflies of September lay eggs, and the lai'Vifi 

 from these feed, and more or less of them matui-e and reach the chrysalis stage, 

 or even the imago, before cold weather comes ; while others, though torpid dur- 

 ing cold weather, are active upon the advent of every fine day, and so feed and 

 mature at intervals throughout the winter months. The butterflies which have 

 emerged in the early part of the winter are typical Ariadne, and a large pro- 

 portion live in a state of semi-hybernation, according as the season permits, and 

 are on the wing in February. Those which emerge late in the winter are mostly 

 of the same type, Avith an occasional variety. (Var. A.) The series in the spring, 

 therefore, begins with Ariadne alone and not with the three forms of the species, 

 for two of them have been left far behind. They lived long enough in the au- 

 tumn to perpetuate the species through the form Ariadne, and nature had no 

 further use for them. Eggs laid in the spring by Ariadne produce Keewaydin, 

 which in its turn is followed by Eurytheme, just as P. Telamotiides is followed by 

 Marcellus. It seems to me that if Marcellus hybernated in the imago and bred 

 with Telamonides or Walshii in the spring, the result would be a variable species, 

 — at any rate, not one seasonally dimorphic. 



