10 
Rowland M. Shelley 
late. Segment 7 of the male, the copulatory segment, must align 
with segment 3, the reproductive segment of the female, which places 
the first modified segments, 9 of the male and 5 of the female, 
opposite each other. Because of this correlation, it is not surprising 
that the species that lack one modification also lack the other, as 
is the case with S. columbianus , virginicus, and australis. Conse- 
quently, the presence or absence of these modifications is taxo- 
nomically important in the northern Rocky Mountains and the Blue 
Ridge Province (Figs. 10, 30), as they enable accurate determina- 
tions of S. columbianus versus S. piger , and S. granulatus versus 
S. virginicus or australis. 
In spot checking males of each species with lobes, I noted 
that the number of leg pairs, the sequence of large versus small 
lobes, and the occurrence of anterior lobes vary among species. 
Table 1 shows the legs that are modified in the species possessing 
lobes; they are absent from the anterior or caudal margins where 
no size is indicated. This variation may hold taxonomic utility, par- 
ticularly for determining males when the gonopods are lost. 
Segments 5-9 in females — In all species except S. columbianus, 
virginicus, and australis, the paranota on segments 5-9 of adult 
females are reduced or absent, resulting in a distinctly narrower, 
Table 1. Comparison of Tibial Lobes of Adult Males of Scytonotus spp. 1 
Segment Number 
Leg Number 
9 
1 13 
10 
14 | 15 
16 
11 
| 17 
12 
18 | 19 
13 
20 | 21 22 
14 
| 23 
piger 
1 
1 ^ " 
C " 
i 
a - | a - 
c - s c - s 
a - 
c - s 
1 
1 a ‘ 
c - s 
i 
a - s | a - s 
c - s c - s 
i 
a - mi 
c - 
1 
l 
insulanus 
la - 
a - 
1 a - 
a - 
1 a - 
a - s 1 a - s 
a-s 1 a-s a-s 
1 
1 c - 1 
c - 1 
1 c - 1 
c - ml c - m 
c - ml c - s 
c - s 1 c - s c - 
1 c - 
bergrothi 
|a - 
a - 
1 a ' 
a - 
1 a " 
a - s | a - m 
a - m| a - m 
l 
|c - 1 
c - 1 
I c - 1 
c - 1 
1 c - m 
c - ml c - m 
c - ml c - 
| 
simplex 
l a " 
c-1 
a - 
c - 1 
1 a " 
■ c - 1 
a - 
c - 1 
1 a " 
c-i 
a - s | a - s 
c - s c - s 
a - s | 
c - 
1 
1 
inornatus 
'a - 
■ 
a - 
1 a - 
a - 
■ a - 
a - s ■ a - s 
a-s * 
1 
I c - 1 
c - 1 
1 c - 1 
c - 1 
1 c - s 
c - s 1 c - s 
c - s 1 
1 
granulatus 
|a - 
a - 
1 a ' 
a - 1 
1 a - s 
a - 1 | a - 1 
1 
l 
|c-l 
c - 1 
| c - 1 
c - 1 
1 c - m 
c - s 1 c - s 
c - 
1 
1 Symbols in the table are: 
a -condition of anterior tibial margin 
c -condition of caudal tibial margin 
1 -large lobes (Fig. 2) 
s -small lobes (Fig. 3) 
m- moderate lobes, an intermediate conditon or small version of the large configuration 
