1332 THE BUTTERFLIES OF NEW ENGLAND. 



nal segments, the sides and dorsum of the hinder abdominal segments and 

 a narrower band along the lower sides of the thoracic segments, the latter 

 bringing the tumid portion into higher relief ; the tumid part is further dis- 

 tinguished by much mottling of lighter and darker colors, particularly in 

 the form of light colored annuli. The chrysalids most nearly resemble 

 those of Papilio but have the angulations still more j)rominent, the ventral 

 bend bolder and the wing-cases more tumid. Their color is brown of 

 various shades, often highly tinged with greenish and always streaked boldly 

 and delicately with black. 



EXCUESUS LI.— SOUTHERN INVADERS. 



They have wandei-'d in their glee 

 With the butterlly ami bee. 



Hemaxs. — And I too in Arcadia. 



Imiviediately upon the close of the glacial epoch, there was a movement 

 of butterflies from the south northward, following by slow steps the retreat 

 of the ice, some at nearer, some at greater distance. It would appear from 

 sundry facts as if this movement were still going on ; at any rate we find 

 upon the southern shores of New England a number of butterflies belong- 

 ing more projierly to the extreme south wiiich are struggling to maintain an 

 existence on our shores, apparently unable to make any further considerable 

 advance to the northward. Such are Junonia coenia, Eii|)toieta claudia, 

 Eurema lisa, Anthocharis genutia, Achalarus lycidas, and perhaps one or 

 two others. In addition to these, certainly, should be mentioned Anosia 

 plexippus, a butterfly belonging to a preeminently tropical type, but 

 which, as I have pointed out, makes annual northward movements of 

 great magnitude, and when summer has closed, retreats again to the south, 

 barely maintaining a permanent existence in the southern districts of New- 

 England. 



Movements from the south northward in the nature of invasions, on ac- 

 count of the large numbers involved, are known to have occurred by direct 

 observation in only a comparatively few instances, but such movements 

 are easily inferred from the sudden abundance of an unknown butterfly or 

 of one comparatively unknown u^jon our southern shores, indicating an 

 attempt on the part of our southern butterflies to invade our territory, and 

 if possible to establish themselves therein. Thus, Chlorippe clyton has on 

 one or two occasions been found in considerable numbers in the immediate 

 vicinity of New York, whereas its proper home is in the far south ; an 

 inhabitant of the middle states as well, it has on these occasions pushed 

 its way to the north, but has not been able to maintain itself permanently ; 

 for it has never been seen within the territorial limits of New England. 

 So, too, Junonia coenia, which has apparently gained a tolerably secure 



