30S ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ber of new crayfish are described, and it would seem as if 

 there were no limit to the number of species of this genus. 

 The same journal contains a list of the grasshoppers of Il- 

 linois by Professor Cyrus Thomas, and a partial catalogue 

 of the fishes of Illinois by E. W. Nelson. 



Insects. 



A notable paper, entitled " History of Phycicdes T/iaros, 

 a Polymorphic Butterfly," by W. IT. Edwards, appears in 

 the Canadian Entomologist. He finds that there are four 

 generations of this butterfly at Coalburg, W. Va.,the first of 

 which is marcia and the second and third tharos, and none 

 of the larvse from these have so far been found to hiber- 

 nate ; and the fourth, under exceptional circumstances, has 

 produced some tharos and more 'marcia the same season, 

 a large proportion of the larvae also hibernating. In the 

 Catskill Mountains there are two generations annually, the 

 first of which is marcia, or the winter form, and the other is 

 the summer form. Mr. Edwards adds that, in a high lati- 

 tude or at a high altitude, we might expect to find this but- 

 terfly with a single brood, and restricted probably to the 

 winter form, marcia. And this is precisely what does occur 

 in the island of Anticosti (about latitude 50) and on the 

 southern coast of Labrador opposite, tharos being the more 

 northern form. All these varieties are produced, according 

 to Mr. Edwards, by changes in climate or temperature. We 

 would add that in this and similar cases studied by Weis- 

 mann, we see species produced by causes easily understood 

 and measured by the ordinary naturalist, and that phase of 

 evolution called "natural selection" does not enter into the 

 matter at all as a vera causa; and we doubt not that Dar- 

 winism, as such, has been much overestimated as a factor in 

 producing species a dogma being mistaken for a genuine 

 cause. 



The annual report of Ilayden's United States Geological 

 and Geographical Survey of the Territories for 1875 contains 

 a report of over two hundred pages, by A. S. Packard, Jr., on 

 the Rocky Mountain locust and other insects either now or 

 likely soon to be destructive in the extreme Western States 

 and Territories. The report is fully illustrated, and con- 

 tains maps showing the distribution of the locust, Hessian 



