proceedings: biological society 409 



tion in the great, down-warped, synclinal areas in South America in 

 comparison with similar areas of the United States. Willis thought 

 them very similar. In many places the areas are covered with woody 

 or reedy vegetation and in some instances the conditions ar? appar- 

 ently favorable for the formation of flat deposits. A. H. Brooks 

 inquired whether the sketch of the southern Andes made by Willis was 

 intended to imply the presence of a peneplain on top of the Andes. 

 Willis thought that a moderately developed peneplain had existed, 

 although it had not been brought to such a stage but that considerable 

 irregularity had survived. Moreover, a good deal of warping had 

 occurred during elevatory doming. Sidney Paige referred to Lowthian 

 Green's theory of a tetrahedral earth, and thought that the general 

 unit character of elevation recently undergone by South America tended 

 to support Green's view. A. H. Brooks inquired as to the origin of 

 fiords along southern coasts. Willis thought they were located in zones 

 of softer rocks which had been cut into by rivers and glaciers. David 

 White inquired whether continental shelves were a marked feature 

 along the southeastern coast where Willis had spoken of recent warping. 

 Willis replied that they were present in some degree of development. 



C. N. Fenner, Secretary. 



THE BIOLOGICAL SOCIETY OF WASHINGTON 



The 540th meeting of the Society was held in the Assembly Hall of 

 the Cosmos Club, Saturday, April 17, 1915, with Vice-President Rose 

 in the chair and 50 persons present. 



Under the heading Brief Notes, L. O. Howard called attention to 

 the development of mosquito larvae and adults in pools of water formed 

 by melting snow in the mountains of New York state, the eggs having 

 been laid on the ground the previous summer in places where pools 

 would be formed. 



The iirst paper of the regular program was by J. D. Hood, Sovie 

 features in the morphology of the insect order Thysanoptera. Mr. Hood 

 gave a general account of the Thysanoptera, called attention to the 

 large amount of systematic work that had been done in it during recent 

 years, and said that it was estimated that about 25,000 forms would be 

 found to exist in the order. He called particular attention to the struc- 

 ture and mechanics of the foot, and to the asymmetrical mouth parts, 

 illustrating the peculiarities of each by diagrams. Mr. Hood's paper 

 was discussed by Dr. Howard. 



The second paper was by E. A. Goldman, Biological explorations in 

 eastern Panama. Mr. Goldman gave an account of his work in con- 

 nection with the Smithsonian Biological Siirvey of the Panama Canal 

 Zone, in 1912, in extreme eastern Panama with a view to determining 

 the faunal relations of that section to the Canal Zone and to western 

 Panama. Very little zoological collecting had previously been done in 

 this region which was scarcely better known than in the 16th Century, 



