OF WASHINGTON, VOLUME XV, 1913. 



27 



3. The hairiness of the eyes in some forms of Tachinidae is a 

 secondary sexual character and is therefor not available as a 

 primary generic character, unless both sexes are known to the 

 describer. 



There are also certain other recommendations which could be 

 adopted to advantage in the study of the Muscoidean flies, namely: 



a. The erection of a genus on a single example of either sex 

 is folly and should not be permitted. 



b. The proposal of a new species on a single specimen or a 

 series representing only one sex is inadvisable. 



c. The creation of either a genus or species on solely chsetotactic 

 characters without a careful study of ample material is unwise. 



d. The variants of a species should be conserved under one 

 species name until good and sufficient evidence is adduced to 

 prove they are otherwise. The splitting of species in the genus 

 Lucilia 1 as practiced by Mr. Townsend is a negative example of 

 what is here meant. 



ANALYTICAL TABLE, CONSTRUCTED ON TEN SPECIMENS OF BELVOSIA BIFASCIATA, 



SHOWING STRUCTURAL VARIATION. 



1 Taxonomy of the Muscoidean Flies, pp. 118-123. 



