40 THE CANADIAN ENTOMOLOGIST. 



But with the Catalogues of Edwards and Strecker before me, and 

 after viewing the varying conflict between Messrs. Strecker and Grote, I 

 would like to ask "What constitutes a species?" There is certainly a 

 wide difference of opinion among authors upon the subject, and if we are 

 properly, and with profit, to read their articles and study their books, we 

 ought to know the basis upon which they work. I am aware there is, 

 properly speaking, in nature, no such thing as a species defined by precise 

 limits. It is impossible to tell where variety leaves off and species 

 begins, and where one species ceases to be one, and becomes two. But 

 when a person becomes (by the fact that he gives a " Check List " or a 

 "Catalogue" to the public) a professed systematise we, "the public," have 

 some right to the ideas of truth upon which their work is based. Apart 

 from right, however, I am sure information on this subject will be of gen- 

 eral interest and profit. May I therefore, ask our friends to " rise and 

 explain ? " Very truly yours, 



Geo. D. Hulst, Brooklyn, N. Y. 



Dear Sir, — 



The paper by Mr. Robert M. Grey in your January number is of great 

 interest. In it Mr. Grey takes the ground that the four Eastern so-called 

 " species " of Limenitis are plastic forms of an original species modified 

 by the environment and with essentially differing ranges in latitude and 

 vertical height. The intermediary individuals which bear out this state- 

 ment, and Mr. Grey's experience in collecting the different forms, are 

 important witnesses to the truth of his discovery. I wish to point out the 

 fact that, in experiments in breeding these different forms, we may not 

 expect to rear all four from one brood of larva?, as a proof of Mr. Grey's 

 correctness. These forms of Limenitis stand evidently in an intermediate 

 position between varieties and species. We may expect, indeed, more or 

 less reversion to be made clear by breeding experiments with them. But 

 we may suppose that these forms, either from climatic or other influences, 

 are partially crystallized. This seems to be inferable from their greater 

 distinctness, more intense than in the cases selected from European 

 butterflies by Weismann and shown in Papilio Ajax by Edwards. Experi- 

 ments will doubtless allow us to arrive at some conclusion respecting the 

 oldest of the forms, which may prove to be arthemis. 



A. R. Grote, Buffalo, N. Y. 



