A STUDY IN VARIATION IN THE NORTH AMERICAN 



GREENBOTTLE FLIES OF THE GENUS LUCILIA, 



WITH SYSTEMATIC NOTES ON THE 



SPECIES INVOLVED. 



By John D. Tothill, 

 - Division of Entomology, Ottawa, Canada. 



Some few years ago the writer had occasion to make a 

 stud}^ in variation of the Canadian species of the genus Lucilia. 

 Series of adults were bred, more particularly in the case 

 of L. sericata Meig., and from the material thus secured the 

 limits and possibilities of variation in certain directions were 

 determined. The fact was brought out that none of the char- 

 acters made use of by Mr. C. H. T. Townsend in his "Taxon- 

 omy of Muscoidean Flies" for the erection of the ten supposedly 

 new species of the genus contained in that publication are 

 of specific value. 



In 1911 an opportunity was afforded of examining the 

 types and cotypes of the above ten species at the U. S. National 

 Museum, in Washington, D. C. The conclusion which had 

 been previously arrived at namely, that the supposed species 

 were only variations of the original four species as recognized 

 by Hough was abundantly justified. 



Exarninations of ' the cf genitalia were made and these 

 again showed that the conclusion was justified. 



It is hoped shortly to publish the results of the study of the 

 <S^ genitalia. 



The present paper consists of the results of the study in 

 variation, and of the examination of the U. S. N. M. Lucilia 

 material. 



A STUDY IN VARIATION IN THE GENUS LUCILIA. 



That variation in external morphological characters is a 

 factor to be reckoned with in systematic entomology is today 

 disputed by no working entomologist. At the same time 

 there are comparatively an infinitely small number of the vast 

 array of insects described to date which have had their limits of 

 variation approximated. 



That such approximation is possible or practical in all cases 

 cannot be entertained; that it is desirable is beyond question. 

 The single historic example of the tachinid fly Exorista {Phryxe) 



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