60 Report of the President 



Invertebrates in General. — Several notable exhibits 

 have been installed in the Darwin Hall in the course of the 

 year. The Annulate Group has been completed; it is one that 

 arouses considerable interest on the part of visitors. A still 

 more elaborate exhibit is that which displays a variety of 

 organisms associated upon the piles of a wharf; it is a repro- 

 duction of a portion of a wharf at Vineyard Haven, Mass. 

 Despite its complexity and the great number of small models 

 that necessarily enter into its composition, this exhibit has 

 been finally completed. In addition to the displays of a faun- 

 istic nature certain other items have been installed. An 

 assemblage of field mice and their enemies, represented in a 

 natural habitat, serves to illustrate the intricacies of organic 

 interrelationships and the consequent struggle for existence. 

 Numerous varieties of dogs illustrate the results of artificial 

 selection that were given special prominence by Darwin. Soon 

 to be placed in the Darwin Hall is a large topographic model 

 of the Island of Tahiti, already completed, which will serve 

 two purposes: it will bear distinctive examples of the land 

 snails under investigation by Professor Crampton, thus demon- 

 strating the principles of geographical distribution, and it con- 

 stitutes one member of the series of models of the Society 

 Islands which in its entirety will show the mode of evolution 

 of a coral atoll from a barrier reef surrounding a volcanic 

 peak. Several other smaller models have been added to the 

 systematic series. 



Much time and labor have been given by the preparation 

 staff of this department to work for other departments; a large 

 and detailed model of the House Fly and a series of models of 

 Bacteria are the most prominent items under this heading. 



Insects. — Marked and gratifying progress has been made 

 in this division during the past year. We have been fortunate 

 in receiving by gift a large number of specimens; Mr. Gross- 

 beck has donated his splendid large collection of Geometridse, 

 Mr. Leng has given extensive series of Coccinellid and 

 Cerambycid beetles, R. D. O. Johnson of Medellin, Colombia, 

 has presented a valuable collection of insects from that 

 locality, and the members of the New York Entomological 



