

148 REVIEWS. 
the saait characteristics of the original genus are reduced to a larval 
but th 






development, though more slowly, and finally reduces its original charac- 
teristics also to a larval See and acquires in the adult state differ- 
ent characteristics from the first series. 
is, with other confirmatory ER VEN] renders it probable that generic 
changes may simultaneously take place in a number of species without 
the loss of their specifle characteristics, and in the same way genera may 
be simultaneously transferred from one suborder ts another without the 
loss of their generic characteristics. The development of generic char- 
acteristics thus appears to be governed by a law which is not dependent 
h 
given in six propositions, from which we quote the two given below 
I. Species have developed from preéxistent species by an inherent ten- 
dency to variation, and have been preserved in given directions and re- 
pressed in others, by the operation of the law of Natural Selection: 
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the same law. 
AN ILLUSTRATED WORK ON THE BUTTERFLIES OF eget oe pae m 
Mr. Samuel H. Scudder will Seats during the coming w 
ral 
careful study; their geographical esiste undue both in and out of New oe 
England, will be largely discussed, and the book virtually form à manual 
for all the Northern United States; it wi i generously illustrated by 
colored 

fres] imer eggs: 
larve and pupse, for illustration and study. Without such assistance it 
would be impossible, in a single summer, to obtain all the requisite mate- 
d e Full credit will be given in the book for every item of assistance - 
— The success with which Mr. Saunders, of Canada, has reared butter- 
flies in their earlier stages, ought to susto our friends to similar 
