9] LEPIDOPTEROUS LARVAE — FRACKER 



ACKNOWLEDGMENTS 



The subject of this paper was suggested by Professor Alexander 

 D. MacGillivray in the fall of 1912. During the two years since that 

 time the writer has become more and more convinced of the necessity 

 for and value of taxonomic studies of immature insects. While a classi- 

 fication based on larvae would doubtless include as serious mistakes as 

 one in which only the adults were considered, combining the two methods 

 results in the elimination of a great many errors. In addition to this 

 purely scientific ideal, the demand of students and economic entomolo- 

 gists for some means of identifying larvae without rearing them has 

 acted as an even stronger incentive to persistent effort. 



The author wishes to express his sincere appreciation of the sugges- 

 tions and criticisms of Professor MacGillivray throughout the prepar- 

 ation of the paper and of the inspiration which has come from association 

 with him. The authorities of the University of Illinois have, through 

 liberal appropriation, made possible the purchase of material from 

 Dr. 0. Staudinger and A. Bang-Haas of Dresden, from the Kny-Scheerer 

 Company, from the Ward Natural Science Establishment, and from 

 Mr. Wm. Beutenmiiller. They have also enabled the writer to study 

 for several months at the United States National Museum, where the 

 series of lepidopterous larvae is probably the most extensive in the 

 world. For securing this assistance, for continuous encouragement, and 

 for placing at his disposal the material of the Illinois State Laboratory of 

 Natural History, the author gives hearty thanks to Professor Stephen 

 A. Forbes. Grateful acknowledgments are due Dr. L. 0. Howard 

 for his courtesy in granting use of the entomological collections of the 

 National Museum. To Dr. Harrison G. Dyar, Mr. August Busck, and 

 Mr. Carl Heinrich, the writer is indebted for numerous suggestions and 

 for making these collections accessible and helpful. 



