BUTTERFLIES OF THE VICINITY OF NEW YORK CITY 
6. Blue Swallowtail (Papilio philenor). 
Common in this neighborhood, but rather local, owing to the 
scarcity of the food-plant, snake-toot (Aristolochia serpentaria). It 
may be found in May and June, and again in August and September, 
in open woods, and in gardens, where the caterpillar feeds on the cul- 
tivated Dutchman’s-pipe (Aristolochia sipho). The butterfly may 
be known easily by the velvety black wings with greenish or bluish 
metallic reflections, and the row of large orange spots on the hind 
wings below. The caterpillar is velvety black with long black and 
orange fleshy tubercles and orange spots. It is found throughout the 
United States and Canada, and in Mexico. 
Subfamily PIERIN-#. 
The species belonging to this subfamily are usually of med- 
ium size, nearly always white, orange or yellow. They have no 
tail-like appendages on the hind wings. The inner border of 
the hind wings is bent downward, forming a channel in which 
the abdomen rests. They are pretty and graceful, with a 
tolerably swift, irregular flight. They are known as white, 
yellow, sulphur or orange butterflies. The caterpillars are 
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