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PROCEEDINGS OF THE NATIONAL MUSEUM 



dealing with populations picked at random along an evenly grading 

 geographic cline. 



A recent attempt on the part of two entomologists to discredit and 

 abolish the concept of subspecies seems to be founded upon the idea 

 that every species is somewhat comparable to a normal spectrum, 

 and that subspecies names represent only narrow strips of color chosen 

 haphazardly and without consideration of intervening gradations of 

 shade. But in those instances where populations of a species are 



Figure 4. — Geographic variation in the gonopods in nine populations of Pachydesmus. 

 Known ranges are represented by the outlined areas; the enclosed figures represent the 

 length of the prefemoral region in terms of percentage of the total length of the telopodite. 

 The letter "d" indicates that the leading edge of the primary tibiotarsus is denticulate 

 or serrate. 



known to maintain their characteristic features over a considerable 

 area without particular intrapopulation variation, and tend to merge 

 with adjoining populations where their ranges meet, I can not see 

 how anyone can reasonably consider the naming of such infraspecific 

 groups as superfluous and misleading. This seems the more true when 

 it is recalled that the same critics of the Latin trinomial suggest replac- 

 ing it by vernacular names alluding to the range of the population 

 being considered. 



Within the specific limits of Pachydesmus crassicutis, I recognize 

 eight subspecies, separable chiefly on the basis of the gonopods, 

 although supplementary correlated differences obtain in the size of 



