70 THE CANADIAN ENTOMOLOGIST. 



were visibly affected, and by the time the tree line was reached — elevation 

 4,500 feet — they were gasping for air. At 2,8co feet, where he was stay- 

 ing, he thought them dead, and finally killed them, as they " gained no 

 strength at the end of twelve hours." Doubtless similar careful observa- 

 tions and experiments with Magdalciia would reveal a similar history. 

 Mr. Scudder, p. 144, thinks it probable that the larval stages cover two 

 winters. If so, the imago is biennial, as C. Bore of Europe, is said to be : 

 " Bore hibernates twice as caterpillar and changes to chrysalis in May, in 

 the winter quarters of the larva, free, in sand, between roots of grass 

 under the surface of the ground." — But. N. E., p. 126. That is, another 

 species of this genus has the larval habits of a noctuid moth.* 



The existence of Magdalena seemed as bad as bad could be, but these 

 accounts oi Semidea indicate a worse climate and therefore severer trials. 

 These are two of the feeblest butterflies in the N. Am. fauna, and this sort 

 of existence has endured at least since the glaciers retreated, and no one 

 can guess how many years longer. f When we read that butterflies have 

 come down from the Tertiary period unchanged, we may allow for 

 Semidea a vast antiquity. 



Members of the Semidea species dwell to-day within the Arctic circle, 

 in Labrador, in the White Mountains of New Hampshire, and in the Rocky 

 Mountains in Colorado, separated by vast distances. Mr. Scudder shows 

 that the mountain colonies cannot exist in the low grounds, cannot even 



* The history of Semidea, as related by Mr. Scudder, mostly from his personal 

 observations, is vvofth the price of the whole work ; and I recommend every person 

 interested in butterflies to make it a part of their library without delay. I differ with 

 Mr. Scudder radically about many things, the restriction of genera, the resurrection 

 of obsolete names, the use of Iliibner's Coitus and Tentameh names for genera and 

 families, but in other important and essential points this work of his is and will forever 

 remain unapproachable. The wealth of illustration is amazing, not only of the butterflies 

 themselves, but of every part and organ of them, and what has never been attempted 

 before except on a limited scale, the eggs and young larva; are shown in greatly 

 magnified and admirably executed figures. In any future system the eggs and young larvae 

 will form an important part. The time is coming when classification based on features 

 of the imago alone will be thrown over, and the new arrangement will take consideration 

 of all three of the preparatory stages. For these matters and "the anatomical details, 

 worked out with wonderful ability, and the life histories and distribution worked out 

 with exceeding care, the Butterflies of New England will be a standard work, and no 

 student can possibly get along without it. The edition is limited and the plates cannot 

 be reproduced ; therefore, I say to my friends, subscribe without delay. 



+ Mr. Geikie, in the Great Ice Age, p. 135, is of the belief that the last glacial 

 period terminated 80,000 years ago, and began about 240,000 years ago. 



