OF BUTTERFLIES 185 



The butterflies I have mentioned sliow an ap2)ar- 

 ent fondness for each other's company, apart from 

 the attractions of the flowers or the muddy road ; 

 indeed, there are very few butterflies which, at 

 the time of their greatest abundance, do not show 

 a tendency to congregate. The Monarch or Milk- 

 weed butterfly (Anosia plexippus), for example, 

 may be seen quite by himself, sailing majestically 

 over the fields, until late in the season, when, hav- 

 ing multiplied to excess, vast swarms are found 

 together ; together they mount in the air to lofty 

 heights, as no other butterfly appears to do, and 

 play about in ceaseless gyrations ; and sometimes 

 they crowd so thickly upon a tree or bush, as by 

 their color to change its whole appearance ; occa- 

 sionally we hear of the migrations of butterflies in 

 swarms, but they are of rare occurrence, and have 

 mostly been observed in the tropics, Mr. W. 

 Edwards, however, relates how, from the top of 

 Pegan Hill, in Natick, Massachusetts, he saw such a 

 moving swarm flying steadily for hours in a single 

 direction. They passed too high for recognition, 

 although, by his description of their size and their 

 mode of flight, it was probably the same butterfly 

 which we have just mentioned. 



The movements of butterflies on the wing are 



