Hopkins — Parallelism in Beetles. 211 



and minor groups and in some cases within the genus. The 

 fact that there is a quite definite relation between the type 

 of the gallery and the systematic position of the species, genus 

 and group indicates that the evolution of the gallery has heen 

 from the simple to the complex and that it has progressed withthe 

 evolution of the species which make and inhabit them, in a similar 

 manner to that of the evolution of human dwelling place from 

 the simple cave to the modern palace. 



The fact that the same or a similar type of gallery is formed 

 by species of widely separated genera and subfamilies can not 

 be so satisfactorily explained, on the theory of phylogeny, as it 

 can on the theory of parallel evolution according to which two 

 or more species, evolving along parallel lines, do things alike at 

 like stages in the evolutionary process. 



Thus we see that parallel modification in morphological and 

 physiological elements is an important factor to be considered 

 in taxonomy. It is evident from a comparative study of the 

 various systems of classification that the failure of taxonomists 

 to fully realize its importance has led to many erroneous con- 

 clusions and much confusion. 



In conclusion, it seems to me that we have two fundamental 

 questions to be answered in regard to the origin, evolution and 

 classification of organisms. 



1. Are the taxonomic characters and characteristics of the 

 species, genus, family, order, class, and kingdom the result of 

 phylogenetic descent from a single ancestral nucleus, through natural 

 selection and the inheritance of selected characters f or 



2. Are they the result of phylogenetic descent from many nuclei 

 tli rough natural selection and natural parallelism f 



I am inclined to the belief that an affirmative answer to 

 the second question would be more nearly in accordance with 

 natural law. 



While phylogenetic descent from a single source is represented 

 by a single genealogical tree, parallelism from different sources 

 may be represented by a forest of genealogical trees with their 

 different elements as near alike as are the branches, leaves, 

 flowers, and fruit of a forest of oak trees. 



