ACKOWLEDGMENTS. 



Referring to Part I, my thanks are due Mr. C. E. McClung, of the 

 Department of Zoology, for the sketch from which figure 4 was made 

 and for the paragraphs upon the egg of Melanoplus differ entialis. 

 Plates I, V, VI, VIII and figure 1 are from photographs taken by the 

 author for this publication. Plate VII and figure 30 are produced 

 from photographs by Mr. Earl Cass, under direction. Figures 2 and 

 3 are from photographs made to be here used by Mr. F. E. Marcy. 

 Figure 11 is from a photograph taken by Mr. E. S. Tucker in this 

 laboratory. All the other plates and figures are produced from original 

 drawings made by Miss Ella Weeks, under the author's direction. In 

 the execution of this work the zeal and fidelity of the artist is worthy 

 of special mention. 



In will be noted from the above that all the illustrations in Part I, 

 both text and plate, have been prepared expressly for this volume 

 from original subject-matter. 



Referring to Part II, I am indebted to Prof. W. C. Stevens, of the 

 Department of Botany, for directing the work of the artist, Miss Weeks, 

 in the preparation of figures 3 and 4, and for the use of the photo- 

 graph, taken by himself, from which figure 7 was made. Plate I is 

 made from four photographs. Plate II is produced from original 

 drawings made by Miss Weeks, under direction. Plate III is from a 

 drawing made after Cheshire. Plate IV figures 5 and 6 are from 

 photographs made by Mr. F. E. Marcy, under the immediate direction 

 of the author. Figures 1 and 2 show in the explanations where taken 

 from ; they were kindly loaned by Chas. Dadant & Son. Figures 8 to 

 29, inclusive, are from photographs taken under the author's direction 

 and with the cooperation of Mr. A. H. Duff. There should have ap- 

 peared in the explanation after each figure the word "(Original)." 



With the exception of plate III and figures 1 and 2, the illustrations 

 were especially prepared for this publication from original drawings 



and photographs. 



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