2l8 ENTOMOLOGICAL NEWS. [May, '08 



Migrating Butterflies. 

 BY P. A. SAVERNER, Highland Park, Mich. 



Point Pelee is a long, tapering point of land, extending from 

 the north shore of lake Erie, about nine miles, near the west- 

 ern extremity of the lake. Out from the Point lie various 

 islands situated like stepping stones across the lake to the Ohio 

 shore. Along this point and its outlying islands, lies a great 

 natural migration route, followed by birds on their vernal 

 and autumnal migrations. During the last three falls I have 

 done considerable ornithological work on the Point, and 1 

 have been much interested in observing that not only do birds 

 habitually use this natural highway in crossing the lake, but 

 that there is a regular and well defined stream of Lepidoptera 

 flowing across in the fall. In the fall of 1905 during our stay 

 from September 4th to I5th, we were greatly astonished at 

 the numbers of Anosia plexippus present. They were to be 

 seen everywhere, in ones, twos or dozens. In the woods, over 

 the fields or along the roadside, and every here and there on 

 the edges of the woods a tree would be found covered with 

 them. One day, along the east beach, one of the few of the 

 small cottonwoods that grow along the top of the sand dune 

 was so covered with them that the whole lee side was a mass 

 of red, their numbers almost hiding the green foliage com- 

 pletely. When we shook the tree they rose in the air in such 

 a cloud that they could scarcely be seen through. We never 

 saw them flying in flocks except when disturbed in some such 

 manner as described above, when they would either fly to an- 

 other adjoining tree in a straggling disorganized fashion or 

 gradually scatter, and proceed, each insect for itself. Individ- 

 uals seldom passed a resting flock but generally joined it and so 

 it seemed that the flocks were built up by the gradual accession 

 of stragglers. 



The next year from September I5th to 22d, we saw the same 

 thing but on not quite so great a scale, due likely to the late- 

 ness of the date. 



This last fall from August 24th to September 6th they were 

 nearly as numerous as during the first season, though we- saw 



