COLIAS IV. 
in the earlier stages, and in the later are often just as much alike. But many 
larvm 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 larvae of Eurytheme 
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 larvce of Philo¬ 
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 progeny the ex¬ 
tremes and all shades of variation. 
And in the Rocky 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 larvm 
from these feed, and more or less of them mature 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, with 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. Telcimonides is followed by 
Marcellus. It seems to me that if Marcellus hybernated in the imago and bred 
with Telcimonides or Walshii in the spring, the result would be a variable species, 
— at any rate, not one seasonally dimorphic. 
