Insect Study 



31S 



THE BLACK SWALLOW-TAIL BUTTERFLY 



Teacher's Story 



HIS graceful butterfly is a very good friend to the 

 flowers, being a most efficient pollen carrier. It 

 haunts the gardens and sips nectar from all the blossom 

 cups held out for its refreshment; and it is found 

 throughout almost all parts of the United States. 

 The grace of its appearance is much enhanced by the 

 "swallow-tails," two projections from the hind mar- 

 gins of the hind wings. The wings are velvety black 

 with three rows of yellow spots across them, the outer 

 row being little crescents set in the margin of the wing; 

 each triplet of yellow spots is in the same cell of the wing 



between the same two veins. The hind wings are more elaborate, 



for between the two inside rows of yellow spots, there are exquisite 



metallic blue splashes, more vivid and more sharply outlined toward 



the inside of the wing and shading off to black at the outside. And 



just above the inner angle of the hind wing is an orange eye-spot with 



a black center. On the lower surface of the wings, most of the yellow 



spots are replaced with orange. 



The mother butterfly is larger than her mate and has more blue on her 



wings, while he has the yellow markings of the hind wings much more 



conspicuous. She lays her egg, just the color of a drop of honey, on the 



under surface of the leaf of the food plant. 



After about ten days there hatches from this 



egg a spiny little fellow, black and angular, 



with a saddle-shaped, whitish blotch in the 



middle of its back. But it would take an 



elfin rider to sit in this warty, spiny saddle. 



The caterpillar has six spines on each segment, 



making six rows of spines, the whole length 



of the body; the spines on the black portions 



are black and those on the saddle white, but 



they all have orange-colored bases. 



When little, spiny saddle-back gets ready 



to change its skin to one more commodious 



for its increased size, it seeks some convenient 



spot on the leaf or stem and spins a little 



silken carpet from the silk gland opening in 



its under lip ; on this carpet it rests quietly 



for some time, and then the old tight skin 



splits down the back, the head portion coming 



off separately. Swelling out to fill its new 



skin to the utmost, it leaves its cast-off clothes 



chnging to the silken carpet and marches back to its supper. 



But after one of these changes of skin it becomes a very different 



looking caterpillar, for now it is as smooth as it was formerly spiny; it is 



now brilliant caraway green, ornamented with roundwise stripes of 



velvety black; and set in the front margin of each of these stripes are six 



yellow spots. In shape, the caterpillar is larger toward the head; 



its true feet have little , sharp claws and look very different from the 



The eggs of the black swallow- 

 tail butterfly, enlarged. 

 Photo-micrograph by M. V. 

 Slingerland. 



