MILLIPEDS — KEETON 5 



not impossible, undertaking. Females with rounded paranota may- 

 be identified as Brachoria with some degree of assurance. Females 

 of species which do not show this character cannot be identified even 

 to genus unless they are found with the males or unless they are gravid 

 and males can be reared from the eggs which they produce. All 

 females treated in this paper were found with males and identified 

 on that basis. 



On the specific and subspecific levels, the male gonopods once 

 again provide the best taxonomic characters. Their shape, relative 

 bulk, and complexity form reliable criteria for separation of the 

 various forms. The major features of the telopodite portion show 

 little variation and the experienced worker can easUy predict the 

 extent of this individual variation even if only a few specimens are 

 at hand. 



The size of the gonopods has been found to be fairly consistent at 

 the species level except in the case of separanda where the great 

 variation may be correlated with geographical distribution. The size 

 of the gonopods is indicated in the descriptions by two measurements, 

 the telopodite arc length and the telopodite arc width. The first 

 of these measurements is made in a plane perpendicular to the telo- 

 podite base line and is the distance from the base of the telopodite to 

 the most distant point on the arc measured in a straight fine. The 

 arc width is measured in a plane perpendicular to the plane of the 

 preceding measurement and is the greatest outside diameter of the 

 arc. For further explanation of these measurements see the drawings 

 of the gonopod of initialis in figure la. 



One gonopod character which has been found to vary somewhat 

 extensively, however, is the size of the prefemoral spine (compare 

 figs. 3a, 3^). Though in some species this is apparently a rather 

 stable character, in othere it varies considerably. If the spine is not 

 only long but of a rather heavy and stm*dy form, it usually does not 

 show much variation. If it is very slender in form even if sometimes 

 quite long, it will apparently exhibit much individual variation. 

 Brachoria insolita is a species that shows much variation in this 

 character (see fig. 6e). 



The shape of the coUum varies somewhat from species to species, 

 but the differences are so slight they are very difficult to use as taxo- 

 nomic characters. The development of the paranotal swellings on 

 the collum and of the ridges running from them along the cephalic 

 edges of the paranota are of considerable use as specific characters. 

 They show sfight individual variation. 



The extent of development of the coxal armature has in the past 

 been considered of some value. This has been found to be quite a 

 variable character, however, and would seem to be of little value 

 except, perhaps, as an aid in separating two species where the typical 



