MILLIPEDS — KEETON 25 



New distribution records: 



Virginia: Grayson County: Mount Rogers, elevation 4,800 feet, Aug. 3, 1955 

 (1 cf ), Hoffman; same location, Aug. 20, 1955 (1 c?), V. P. I. expedition. Wash- 

 ington County: Konnarock, Aug. 2, 1941 (1 cf); Neals Farm near Damascus, 

 Aug. 18, 1941 (1 cf , 2 9 ), Dr. and Mrs. S. T. Brooks. 



Discussion: This species brings to our attention one of the most 

 interesting problems in diplopod taxonom}^ that of subspeciation. 

 For many years it has been customary to designate each new form as 

 a full species. This has often been a justified procedure inasmuch 

 as many of the forms concerned have been known from only a few 

 specimens and ranges have been poorly understood. 



More recently, however, systematic collecting has often revealed 

 the presence of intermediate forms so that it is now known that 

 what were formerly considered full species are actually geographical 

 populations forming distribution series with intergrades occurring at 

 the borders of the populations. 



This phenomenon has been studied in several genera of the 

 Xystodesmidae by Hoffman (1951) and he has considered that it 

 represents subspeciation of a type comparable with that found in 

 many vertebrate groups such as fish, amphibians, reptiles, etc. 



Some workers have recently been rather strong in their denunciation 

 of the subspecies concept. They maintain that the subspecies as now 

 used has no reality and only tends to confuse understanding of varia- 

 tion and to add a needless multiplicity of names. It is my belief that 

 this criticism goes too far. It is true that the subspecies concept must 

 be used with caution and that it has often been misused. This does 

 not mean, however, that the concept is invalid or should be abandoned. 

 There are in biology many instances of continuous clines of variation 

 and it seems obvious that attempts to arbitrarily delimit stages in 

 these continua and call them subspecies are ill-advised and can only 

 be misleading. The value of the subspecies category is apparent in 

 those cases where the spatial isolation of the unit populations is more 

 nearly complete. 



It is my feeling that Bmchoria eutypa illustrates a case where sub- 

 species designation is not only appropriate but is the most adequate 

 method of describing the facts as they are now known. In addition 

 this species provides a good example of clinal variation. 



Brachoria eutypa was described by Chamberlin from Hamblen 

 County, Tenn., in 1939. In 1942, Chamberlin described Brachoria 

 ethotela from Marian, Va. These two forms differed from each other 

 in several particulars. The postcingular portion of the telopodite 

 of the male gonopods is often considerably longer and somewhat 

 thinner in eutypa. The distal end of the telopodite of ethotela is 

 heavier and shghtly more complex. In addition, eutypa has the tri- 



