FORBES: LEPIDOPTERA 551 



show whether the nymphalid and noetuid schemes can be homologized definitely, 

 but the absence of similarly definite schemes in the skippers, Castniidae, and 

 Cossidae reduces our hope. The little work done on the physiological forces be- 

 hind the forming of these patterns is too scattered to summarize. 



The knowledge that coloration and patterns were protective by matching 

 normal backgrounds, greatly antedates our time, but mimicry was a discovery 

 of nearly one hundred years ago and was impressed on Bates (1862) by the 

 wealth of examples he saw along the Amazon. A few years later, Miiller was also 

 impressed by the many cases he saw, farther south in Brazil, in which more 

 than one member of a pattern appeared about equally protected, and proposed 

 what we now call IMullerian mimicry (convergence of pattern to simplify the 

 learning process, and thus to reduce the number of individuals sacrificed by in- 

 experienced predators). Realization by North Americans that mimicry is also 

 (though feebly) a North American matter dates from Scudder's Essay of 1889. 

 Looking back we can date mimicry in a negative way to Linnaeus, for undoubt- 

 edly it was the handling of unrelated models and mimics with similar patterns 

 that caused him to abandon, in his tenth edition, the very useful distinction of 

 four-footed and six-footed butterflies. 



For a full analysis of the problems involved in coloration, the critical work 

 is certainly Gerald Thayer's Concealing Coloration, and the date is 1909. This 

 work showed fully the functions of concealing pattern and color, mimicry, both 

 tentative and developed, and added flash colors, ruptive pattern, and counter- 

 shading — all largely illustrated by the Lepidoptera.^ Later work has added many 

 details, but little theory, much of which is summarized (without deep insight) 

 in volume 2 of Schroeder's Handhuch (1929). 



In the field of genetics the Lepidoptera have served from time to time, 

 mainly at first in the breeding of families of specimens to obtain lots with aber- 

 rant patterns, and lots of material distributed by several dealers in the period 

 after 1900 have been better known than the widely scattered publications. Sei- 

 fert did some significant work in the early 1900's showing Mendelian inheritance, 

 but his published reports in 1901 and 1905 do not deal with the genetics, which 

 must be studied from his material preserved at the American Museum. AVhiting 

 worked on Ephestia kiiehniella, and published some data on the genes in 1919, 

 but soon abandoned the moth for its hymenopterous parasites. But the most 

 important work based on the Lepidoptera was that on the gypsy moth, carried 

 on by Goldschmidt over a period of many years, which threw light on the physi- 

 ology of variation and the control of sex. It is summarized, with much other 

 related material, in his Physiological Genetics (1938). 



Geography 



The Lepidoptera are a very important source of data for zoogeography, since 

 in various groups we understand the classification well enough to distinguish 

 between true relationship and parallelism; the material is widely collected, and 

 the means of distribution are pretty well understood. Also, from the days of 

 Wallace and Bates we have had workers interested in both Lepidoptera and 



3. An interesting side note is the fact that Theodore Roosevelt used his term "nature- 

 faker" chiefly of the Thayers — and it was they who turned out to be right. 



