WITH FURTHER HISTORIES. 169 



climatic conditions. The illustrations here given 

 show well the difference between these varieties, 

 but if they were colored, it wonld be even more 

 marked. 



These are examples of simple or pure dimor- 

 phism, as the others were of seasonal dimorphism ; 

 but what if we have these mixed \ and what if, 

 at the same time, we 

 have that commingling of 

 broods which results 

 from premature hiberna- 

 tion of chrysalids ? We 

 have one conspicuous ex- 

 ample of this complica- 

 tion, of such interest that 

 it is worth while to give 

 the history of the insect 

 in full. It is the Zebra 

 Swallow-tail (Iphiclides 

 Ajax), a butterfly whose 

 northern limits barely FIG. 145. iphiciides Ajax, form 



-, -VT -\r i -i _c Walshii, nat. size. 



reach New York, and for 



whose history we are indebted to the perseverance 

 of Mr. Edwards of West Virginia, -whose obser- 

 vations have been so often mentioned here. 



This author has not only indisputably estab- 

 lished the identity of two forms previously de- 

 scribed as distinct species, but has proved the 

 existence of a third permanent form and has ad- 



