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THE AMERICAN NATURALIST [Vol. XLTII 



student to have access to original descriptions. Xo one is able 

 to tell when an apparently useless character (from the system- 

 atise standpoint) and therefore one invariably omitted from 

 keys, may not assume prime importance in the light of unnamed 

 material. The practical difficulty that one has in depending 

 upon literature and concise revisions is this. By testimony of 

 keys and fi.mires too) one may have a species very close to a 

 named species, yet there may be present in the questionable 

 form additional characters of which no mention is made in keys. 

 If one has not access to the original or some later authentic 

 description he is "up a stump." The writer has so often 

 found himself in this undesirable position that he speaks with 

 some feeling on the subject. 



However, the lack of descriptions is partly compensated for by 

 the excellent notes under "Remarks." and in some cases by the 

 republication of figures. Students of the group have every 

 reason to be grateful to Dr. Clark for a very timely and useful 

 memoir, and one which has in several instances reduced to 



W. K. Fisher. 



LEPIDOPTERA 



The Blue Butterflies of the Genus Celastrina.— In the second 

 volume of Mr. J. W. Tutt's "British Butterflies," recently pub- 

 lished, is a most exhaustive account of the small blue butterflies 



