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mainly on the entomology of the Biological Station field, one 

 each on the (Jdonata, the EpJionerida, the fresh-water .Vo^///.sr^;, 

 and the aquatic Colcoptera. The order of procedure which I 

 have endeavored to pursue in the preparation of these papers, 

 and which seems to lead to the most satisfactory and accurate 

 results, is as follows : First, the collection of a large quantity of 

 material and data under the greatest possible variety of con- 

 ditions as to locality, surroundings, stage of water, season and 

 time of day ; then the careful study of these, in connection with 

 the literature, and the making of copious notes and sketches 

 preliminary to the preparation of manuscript, all evident 

 deficiencies either in material or data being carefully noted 

 down ; next, a return to the field at the times and places indi- 

 cated by the previous collections for the special purpose of 

 supplying, as far as possible, these deficiencies, and finally, 

 after further study of the literature, the writing of the manu- 

 script. 



In the preparation of the pmper on the Odonaia I have had 

 the valued assistance of Prof. J. G. Needham and Mr. C. C. 

 Adams, who have furnished the systematic work on the nymphs 

 and adults respectively, while it has been my part to discuss 

 the biology and oecology of the group and of its species and to 

 combine the several manuscripts into a single paper — now 

 nearly ready for the press. Under Mr. Adams's supervision the 

 State Laboratory Artist, Miss Hart, has prepared a valuable 

 series of 134 drawings illustrating the abdominal structures of 

 nearly all our Illinois species, and a series of general drawings 

 of the nymphs and their distinguishing structures is well 

 under Avay. 



For the article on the Ephemerida, the Station collections 

 and notes have all been examined and the results are nearly 

 ready to be put into manuscript form. It would add greatly to 

 the usefulness of the paper, however, if a study of the large 

 series of nymphs of this order in the general collections of the . 

 State Laboratory could be made before the article is completed. 



Much time and labor have been spent on the Mollusca in the 

 endeavor to place the study of this group on a truly scientific 

 basis. Not merely the shell, but all parts of the animal were 

 studied, full use l)eing luado of the unusual facilities at the 



