1960 ] 
Christiansen — Genus Pseudosinella 
9 
are common ; rarely, specimens appear with fewer, as can be seen in 
those from Tennessee which have from none to six per side. The 
tibiotarsus of this population is slightly longer than is normal for the 
species, but they are otherwise similar to forms seen elsewhere. This 
would appear to be an example of cave evolution proceeding within 
a population and would be worth additional study. Pigment may be 
uniformly distributed over the whole body or limited to the head 
region. The apical organ of the third segment varies from the condi- 
tion described to two subcylindrical pegs. 
The identity of this species with the European specimens is still in 
doubt as no comparisons could be made; however, there appears to be 
good agreement between the descriptions and the specimens at hand. 
This species may very well be the same as P. collina , which was de- 
scribed by Wray (1952) as having only two internal ungual teeth; 
but until this can be checked the two species must be considered sepa- 
rate. 
Pseudosinella dubia, new species 
Figures 6-1 1 
Facies typical of genus. Background color white with an overall 
scattering of blue pigment, particularly dark on dorsum of head where 
it forms a diamond shaped mark between the eye patches. Head 
broadly oval; eyepatches elongate trapezoids, each bearing five eyes 
in two groups, an anterior group of three and a posterior group of 
two. Antennae about one and one half times as long as the cephalic 
diagonal ; first three segments subcylindrical and fourth segment fusi- 
form. Fourth segment dorsally with numerous blunted smooth setae 
of several different sizes and shapes; apical organ of third segment 
with two irregular flattened elliptical rods in a fold, and about fifteen 
additional blunt curved setae scattered over the inner ventral surface 
of the segment. Second thoracic segment markedly humped forcing 
the head into a slightly hvpognathous position. Fourth abdominal 
segment about five times as long as third. Unguis with minute basal 
external tooth and three small internal teeth, with basal-most inner 
tooth on a level and frequently appearing as one under low magnifica- 
tion. Empodial appendage lanceolate, with a small but clear external 
teeth, exceeding the level of the unpaired internal ungual tooth. Ten- 
ent hair weakly clavate. Mucro with apical tooth about twice as long 
as subapical, and markedly upturned ; basal spine exceeding the apex of 
subapical tooth. Anterior macrochaetae as follows: on dorsum of 
head four interantennal setae, the posterior pair closer together, and 
