VI PREFACE 



remaining photographs, not accredited, have been pho- 

 tographed from nature or preserved specimens by the 

 author for this work. 



The author wishes to express his thanks to Miss 

 M. E. Wise for the drawings 'which bear her name, to 

 Professor M. V. Slingerland for photographs, to Pro- 

 fessor E. A. Birge for the nse of electros for figures 5G 

 and 58, to Mr. M. B. AYaite for the nse of electros for 

 figures 72-84, to the Century Company for the electro 

 for figure 65, to the Goulds Company for electros used 

 for producing figures 231-234. Specific acknowledg- 

 ment accompanies each of these illustrations. 



Material assistance in the preparation of this work 

 has been given by Professor \Y. C. Stevens, who has 

 kindly loaned a number of photographs, and has read 

 chapter VII both in manuscript and proof; by Pro- 

 fessor V. L. Kellogg, who has made valuable sugges- 

 tions; by Dr. S. AA T . AYilliston, who has read the proof- 

 sheets on the classification of Diptera ; and by Professor 

 C. E. McClnng, who has very kindly read the entire 

 book in proof form. An expression of the author's ap- 

 preciation is but a slight token in recompense for the 



value of these courtesies. 



SAMUEL J. HUNTER. 

 UNIVERSITY OF KANSAS. 



