THE CANADIAN ENTOMOLOGIST, 119 



Mr. Fiske came near proving a point concerning which many of us 

 are interested, but the weak point is this : Did he examine the leaves of 

 the branch of elm on which he netted the 9 Umbrosa ? If not, how 

 does he know that there were no eggs upon the limb at the time of con- 

 fining the 9 there ? 



I have frequently found upon the same limb larvae of Graptas in 

 several stages of maturity, small ones just hatched, and others almost 

 ready to pupate. 



I am inclined to think that Umbrosa and Fabricii may be obtained 

 from eggs laid by one $ , just as Mr. W. H. Edwards has succeeded in 

 raising imagoes of Papilo Orego?iia and Bairdii from eggs laid by a single 

 individual. 



To prove these points just as we would have them, both sexes should 

 be reared, each form paired with its kind, and vice versa, and the results 

 noted. The second generation of specimens thus observed should settle 

 the question. 



While I cannot positively answer Mr. Fiske's question as to where 

 the immense number of Umbrosa came from, the observations made here 

 go to prove that the uncommon appearance of the species was not con- 

 fined to one locality, but the "wave" probably extended over the entire 

 eastern United States. It is my opinion that the preceding autumn was 

 an unusually favorable one for the Graptas, for both Umbrosa and Fabricii 

 were common here in August, 1895. 



Grapta Comma was very abundant here in the autumn of 1892, but 

 did not appear in great numbers again until the spring of 1896. 



Papilio Ajax is very rare here in ordinary years, but in 1895 sud- 

 denly great numbers of badly worn specimens appeared and remained for 

 some days. Every collector captured examples, I think, but hardly any 

 one secured a perfect specimen. 



The nearest point at which the food plant of Ajax is found, so far as 

 1 have been able to ascertain, is on the Michigan side of Lake Michigan. 

 In this case the butterflies may have been carried from their usual haunts 

 by winds. 



Insects undoubtedly migrate, sometimes suddenly and in immense 

 numbers, as has been noted oi Daiiais Archippus and Callidryas Ejtbuie, 

 and sometimes slowly, taking years to reach a certain locality hitherto 

 unknown to the species. 



Chrysophanus Helloides is moving eastward. A few years ago it 



