90 BUTTERFLIES 



to ascertain definitely whether the insects thus oriented 

 themselves at the time of alighting, so that their wings 

 presented the least resistance to the force of the wind, or 

 whether this was a mechanical result of the breezes. 



The Great Southern White 



Pontia monuste 



There used to be in the Northern states before the ad- 

 vent of the Imported Cabbage butterfly a familiar white 

 butterfly which then laid its eggs upon cabbages in much 

 the same way that the imported pest now does. One who 

 has seen this northern Gray-veined White and then sees 

 the Great Southern White will be likely to think of the 

 latter as a larger edition of the former, for in the males of 

 the southern species the wings are practically white save 

 for a narrow dusky border at the outer angle of the front 

 pair, although in the female this dusky margin is wider 

 and the hind wings show a series of dusky triangles near 

 the margin. There is also a curious black marking 

 suggestive of a crescent on each front wing near the 

 middle of the front border, which helps to make the 

 appearance of this butterfly very distinct from that of any 

 other. 



Although this species is at times so abundant that it 

 swarms in great flocks and although it has been known for 

 many years, its life-history seems not to have been care- 

 fully worked out since it was first described by Abbott 

 more than a century ago. The caterpillars feed upon 

 cruciferous plants and when full grown are about an inch 

 and a half long, of a general yellow color, more or less 



