38 THE CANADIAN ENTOMOLOGIST. 



duct in New England as elsewhere of the form Fabricii. Our author 

 proceeds: " The reason for this variation " (that is, between the dimor- 

 phic forms) " is difficult to explain, as neither food nor atmospheric change 

 appear to have anything to do with it, for we find that Mr. Edwards has 

 produced both forms where the larvae were found under precisely the same 

 circumstances." Both the forms spoken of are figured in But. N. A., vol. 

 I, and the life history at Coalburgh is given at length. Also in C. E., x., 

 73, and xiv., 201. I gave the result of many years observations at Coal- 

 burgh on this species, stating that all the hibernating butterflies had been 

 Fabricii, except in a single instance ; that the eggs laid by females of this 

 early Fabricii produced a mixed brood, the large majority of individuals 

 being Umbrosa. And eggs of Umbrosa, of this mixed brood, again pro- 

 duced a mixed brood, the large majority still being Umbrosa. But that 

 eggs of these last Umbrosa had produced Fabricii only, late in the year, 

 and these were hibernators. At the north, where there are two broods 

 only, the dimorphism is complete, and this is the case with all seasonally- 

 dimorphic species of butterflies, which are also only two-brooded. But 

 at the south, or where the length of the warm season permits one or more 

 additional broods to mature — and these seem to be inserted between the 

 two original ones — the result in such additional broods is a mixture of the 

 two forms. But in the case of Iiiterrogationis, there is a preponderating 

 tendency towards the summer form, Umbrosa, imperfectly counteracting 

 the mherited tendency of the species to produce the winter form Fabricii^ 

 as it would in New England. 



These results are not only interesting but biologically very important, 

 and the forms are not to be regarded as simple variations. Food has 

 nothing to do with dimorphism, nor has atmospheric change, but climate 

 has. Vide Weismann, vol. i. In my paper referred to, Can. Ent., x., 

 p. 73, I offered a conjecture that at the north, Fabricii would be found to 

 be the winter form and Umbrosa the summer, and expressed a hope that 

 some lepidopterist would examine into the matter and report. If Mr. 

 Sprague has made the necessary observations, I hope he will publish them. 

 Under Melitaea (Phyciodes) Tharos, we are told that the larvae of first 

 brood give the " butterflies known as Morpheus,'' while the larvae of the 

 second hibernate, to produce " the butterfly known as Myrifia," in June. 

 That is a mistake for Alarcia. But here again the names of the forms 

 had to be used to make the story intelligible. 



Satyrus Alope is given as one species, 6". Nephele as another, though 



