188 MANUAL OF VEGETABLE-GARDEN INSECTS 





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Fig. 112. — Caterpillar of the black swallow- 

 tail butterfly suspended for pupation 

 (X f). 



more distinct and on the hind wing the inner row of 

 spots is replaced by a broad yellow band. In the North the 

 butterflies emerge from over-wintered pup?e in May and June 

 and deposit their eggs singly on the upper side of the leaves of 



the host plants. In 

 Florida the butterflies 

 hibernate. The egg (Fig. 

 110) is globular, about 

 ■^ inch in diameter, pale 

 honey-yellow when first 

 laid, changing to reddish 

 brown in parts. The 

 eggs hatch in about ten 

 days. In the first stage 

 the caterpillar is about 

 1^ inch in length, black, 

 banded about the middle 

 and rear end with white. When mature the caterpillar 

 is about 2 inches in length, green, and each segment has a 

 black band near the front margin inclosing six yellow spots. 

 When disturbed this caterpillar has the habit of extruding a 

 pair of orange-red horn-like 

 scent organs from the dorsum 

 of the prothorax (Fig. 111). 

 These organs are known as 

 osmateria and are probably 

 for defense. The caterpillars 

 become full-grown in three to 

 four weeks and suspending 

 themselves by a silken girdle 

 (Fig. 112) transform to pup?e on some nearby support. 

 The pupa (Fig. 113) is 1^ inches in length, light dirty 

 brown marked with black and dark green. It is attached 

 to its support by a button of silk at the hind end of the body 



Fig. 113. — Chrysalis of the black 

 swallow-tail butterfly (X fo). 



