M 



THE AMERICAN MIDLAND NATURALIST 



first day, and after the twenty-third there was no noticeable evi- 

 dence of migration, though Monarchs were not uncommon. 



In 19 1 6 I saw large numbers of Monarchs on September 5, but 

 the true migration did not start until the eleventh, and two days 

 later I found thousands of the butterflies at the oak grove, with 

 constant flights to the southeast. I at once went to a little, sunny 

 valley some three and one-half miles to the southeast and there I 

 found conditions comparable to those at the oak grove on Septem- 

 ber 17 of the year before. The flock was alm.ost entirely composed 

 of Monarchs, and from a short distance many of the trees had the 



SkET CH' n/KT 1*^ 



SH OWI MC; I flSETCT 

 MIQR/^TIOH T?OUTES 



IfiPuOYD AfiD CERf?0 CORDOJ 



•-^i-KNowN L I M Es OF Flight I 



<5^=-pgoBABLe L iriE S OF Pl IQHTJ 



appearance of being in autumn colors, the butterflies were so 

 thickly gathered. On and by the road over which I went to the 

 valley I had seen large flocks of Colias philodice, .with considerable 

 numbers of Monarchs, but I was unable to determine whether or 

 not the former were in actual migration. On September 16, I 

 saw a large flock of Monarchs and Clover Sulphurs flying east and 

 south, and with it were numerous individuals of .the European 

 Cabbage Butterfly (P-ieris rapae). I first saw this fiock some two 

 miles from the oak grove, and I was curious to know whether or 

 not this flock, which was quite distinctly marked by the unusual 

 presence of P. rapae, would rest at the grove. As I was walking, 

 some forty minutes elapsed from the time when I first saw the 

 butterflies and the time when I arriv^ed at the desired locality. 

 Here I found that there were numbers of Anosia plexippus, Colias 

 philodice and also Pieris rapae, so in all probability the flock that I 



