ROBERT EVANS SNODGRASS — THURMAN I3 



pletely accurate in detail in a style which can be read and appreciated 

 by both specialists and laymen. Dr. Snodgrass's continued study of 

 evolution, for which he was branded a heretic in 1894, is evident in 

 his discussion of the Diptera. "Scientifically, the Diptera are most 

 interesting insects, because they illustrate more abundantly than do 

 the members of any other order the steps by which nature has achieved 

 evolution in animal forms. An entomologist would say that the Dip- 

 tera are highly specialized insects ; and as evidence of this statement 

 he would point out that the flies have developed the mechanical possi- 

 bilities of the common insect mechanism to the highest general level 

 of efficiency attained by any insect and that they have carried out 

 many lines of special modification, giving a great variety of new uses 

 for structures limited to one mode of action. But when we say that 

 any animal has developed to this or that point of perfection, we do 

 not mean just what we say, for the creature itself has been the passive 

 subject of influence working upon it or within it. A fundamental 

 study of biology in the future will consist of an attempt to discover 

 the forces that bring about evolution in living things." 



"Principles of Insect Morphology," published in 1935 (53), is con- 

 sidered by many to be the masterpiece of Snodgrass. It is described by 

 Dr. Hans Sachtleben (Deutsches Entomologisches Institute, vol. 3, 

 pp. 676-677, 1953) as the "greatest work." Dr. Clarence Hamilton 

 Kennedy (Science, vol. 83, pp. 413-415, 1936) deemed this text to 

 be "a volume of interest to zoologists as well as to entomologists." 

 Dr. Kennedy acknowledged the abilities of the author and noted the 

 careful writing of the book, that it is not just an expansion of lecture 

 notes into chapters. "It is this remarkable ability to see things, then 

 to draw them in a superb style that makes an outstanding anatomist 

 . . . [the] ability to see the riches in the common and abundant, to 

 organize and interpret the commonplace is one of the characteristics 

 of a genius. . . ." And so for more than 20 years "Principles of In- 

 sect Morphology" has been and still is the leading text dealing with 

 insect structure. Copies have been printed in numbers approaching 

 9,000 for the use of students and specialists throughout the world. 



In explaining the difference between "anatomy" and "morphology," 

 Dr. Snodgrass tells us that "anatomy is what you see with your eyes, 

 morphology is what you think you see with your mind." The recorded 

 facts of anatomy, he points out, do not change much with the years ; 

 but morphological concepts vary according to the mental vision of the 

 morphologist. The zoologist, however, should continually revise his 

 morphological outlook as new facts come to light. Through the years 

 a few students of morphology have not agreed fully with the morpho- 



