258 ^ THE CANADIAN NATURALIST. [Aug. 



So among classes, the nerve class in eacli province is the highest 

 and the embryonic class the lowest, and the other two interme- 

 diate ; but the idea of rank is not here the primary one, as it is 

 in forming the orders. It is also true that from the province 

 downward the idea of type or plan is constantly before us. 



We have now in descending from provinces reached the genera 

 and species, with the consideration of which we commenced ; and 

 if the preceding views have been understood, we shall be prepared 

 to commence the study of Descriptive Zoology, or to enter upon 

 the details which fill up the outline which has been sketched. 

 In doing this we must take specimens of known species and 

 study them in their structural and physiological peculiarities, and 

 in their relations to the other species congeneric and co-ordinate 

 with them. 



ON THE OCCURRENCE OF PIERIS RAP^E IN CANADA. 



By G. J. Bowles, Sec. Ent. Soc. of Canada, Quebec Branch. 



During the summer of 1863 — my first collecting season — I 

 captured in the vicinity of Quebec numerous specimens of a but- 

 terfly of which no description could be found in any work on 

 American entomology. Mr. Couper, to whom I applied for 

 assistance, was equally at a loss to determine the species, con- 

 sidering it, as I did, to be indigenous to Canada. In order to 

 solve the problem, however, he forwarded some specimens of the 

 imago to Mr. William Saunders, of Loudon, C. W., who pro- 

 nounced them to be identical with Pieris rcqjce, the small white 

 butterfly of England, one of the most common and injurious 

 lepidopterous insects of that country. In the meantime I had 

 enclosed a drawing of the butterfly, together with the wings, to 

 Mr. S. H. Scudder, of Boston, Mass., from whom I received a 

 reply, stating that after comparing the drawing and wings with 

 specimens of P. rajjce in the Museum of Comparative Zoology 

 at Cambridge, he saw no reason to consider them distinct : at the 

 same time he desired further investigation to be made respecting 

 the larva and pupa states of the insect. This investigation has 

 been successfully carried out, and places beyond doubt the iden- 

 tity of the butterfly with the English P. raj^cv, thus establish- 

 ing another instance of the transportation of a lepidopterous 

 insect across a wide expanse of ocean, and its naturalization in 



