AMERICAN MIDLAND NATURALIST. 179 
ported. Mr. Ellis has collected in most sections of the State 
during the past two or three years and we therefore have a 
means of determining changes that have taken place during 
the last eighteen years. 
The giant sulphur, Callidryas ebule, was reported only 
from Vanderburgh County in 1891, where a local collector, $. 
G. Evans,“took from one to half a dozen almost every season.” 
Mr. Ellis took three at Vincennes in 1906, several in 1907, and 
several in 1908, and says that it was very common there in 
9, as many as a dozen being seen in the course of an hour. 
The food plants are cassia, wild senna and clover. These are 
not of recent introduction and the present increase of the but- 
terfly is not due to a change in food supply but probably to a 
northward migration along tributaries of the Mississippi. 
e black swallowtail, Papilio polyxenes, was said by 
Blatchley to be, next to the giant swallowtail, the rarest but- 
terfly of the group. Mr. Ellis says that it is now the most 
abundant of the swallowtails in every part of the State, and 
even one of the commonest of all butterflies. The larvae feed 
upon the wild parsnip and other Umbelliferae and these are, 
for the most part introduced plants that have become common 
only in recent years. | 
n six years collecting Blatchley saw only two living speci- 
mens of the giant swallowtail, Papilio 'cresophontes, finding 
none at Bloomington, “although a constant outlook has been 
kept for it." Ellis says it is still our rarest Papilio, but it is 
fairly common throughout the State. He has taken it at 
Bloomington, Mitchell, Shoals, Vevay, Indianapolis, Anderson 
and Winona Lake. I have myself seen as many as fifteen in 
one afternoon, my zoology class having taken ten or twelve 
in the course of an hour between Milford and Syracuse in 
Kosciusko County. The food plants are the hop tree and 
prickly ash and these must be on the decrease, although still 
common in many places. The reason for the increase of the 
butterfly is probably a northward and eastward migration of 
the species. This movement was noted some years ago by 
Edward 
s. ; 
Scudder, in 1886, reported the gray emporer, Chlorippe 
celtis, from the extreme southwestern tip of ndiana. In 
The 
native of Guatemala and has migrated northward through 
