40 CLARK —NEW AMERICAN SPHINGIDAE gee 
be to give a list of my many friends in the entomological world. 
A few, however, I must speak of. It was due to the encourage- 
ment first given me by my friends William Schaus, Andrey N. 
Avinoff, Dr. William Barnes and Dr. J. McDunnough, that I have 
had the courage to attempt the description of new forms. The 
officials of all the great American museums have given me every 
facility in the study of their collections and in the exchange of 
specimens. I wish to acknowledge the many courtesies of the 
American Museum, the Brooklyn Institute, the California Acad- 
emy, the Carnegie Institute, the Field Museum of Chicago, the 
Museum of Comparative Zoédlogy, the National Museum, and the 
Philadelphia Academy. Especially are my thanks due to Dr. 
William J. Holland, Dr. Frank E. Lutz, Mr. Frank E. Watson, 
Mr. Jacob Doll, Mr. Samuel Henshaw, Dr. Henry Skinner, Prof. 
Charles B. Cory, Mr. William J. Gerhard, and Mr. William C. 
Wood, all good friends of mine, for their assistance and instruction 
in many ways where I have needed help. 
I am indebted to Rev. A. Miles Moss of Para, Brazil, for the 
opportunity of knowing something of the larval life of the South 
American Sphingidae, a subject in which his knowledge is so 
remarkable. From across the water, Dr. Karl Jordan, Mr. Paul 
Dognin, and Mr. Charles Oberthur have given me their cordial 
assistance and have been patient with my ignorance. Any refer- 
ence to the Sphingidae would be incomplete which did not again 
say that the lasting thanks of all lepidopterists are due to Dr. 
Walter Rothschild and Dr. Karl Jordan for their wonderful ‘Re- 
vision’ of that family, which has placed its classification on the 
modern scientific basis of structural differences. 
It is highly probable that mistakes will be found in my observa- 
tions; for these I alone am responsible; while for whatever sum 
total of value and accuracy my descriptions may have, my thanks 
are due to those who have so greatly helped me. I am only giving 
an experience which must have been shared by many others when 
I say that the pleasure of coming to count as friends so many men 
of rare personal charm, as well as of great scientific knowledge, and 
of codperating with them to the extent of my ability, has given an 
added happiness to a pursuit sufficiently fascinating in itself. 
