THE SWALLOWTAILS 67 



in the other caterpillars of this genus, but the odor emitted 

 by them is likely to be less pronounced than usual. 



When full grown the caterpillars find such shelter as 

 they may and each spins a bit of silken web and a silken 

 loop which hold it while it changes to the chrysalis. This 

 chrysalis is very likely to take on the colors of the immedi- 

 ate surroundings and thus be rather difficult to see. If the 

 egg was laid by one of the spring or early summer butter- 

 flies, the chrysalis will soon change to a butterfly which 

 will appear toward midsummer and which may lay eggs 

 for another brood of caterpillars. These caterpillars 

 mature to chrysahds the same season and some of them 

 are believed to change into butterflies in autumn, these 

 butterflies hibernating through the winter; while others 

 are believed to remain unchanged through the winter 

 and disclose the butterfly the following spring. This is an 

 exceptional condition for the Swallowtails and it is worth 

 while to make careful observations along its northern 

 limits to learn more definitely the facts as to the winter 

 condition. 



The Green-clouded Swallowtail 



Papilio troilus 



This beautiful butterfly is essentially a southern species 

 and is found over a wide range of territory from the Mis- 

 sissippi River to the Atlantic Ocean. It occurs as far north 

 as New Hampshire and Vermont and has even been re- 

 ported from Alberta, Canada. It is easily recognized by 

 the blue-green clouding of the upper surface of the wings, 

 the general color being velvety black with distinctive 



