392 
Psyche 
[December 
Table 3. Scale attachment densities for the wings of three pierid butterflies. 
Attachments/ mm 2 Area/ sample (mm 2 ) Sample 
Species 
Area 
X 
SD 
X 
SD 
size 
N. iole 
sex brand 
662.9 
156.9 
0.050 
0.003 
5 
discal cell 
393.1 
22.4 
0.144 
0.106 
4 
E. nicippe 
sex brand 
974.3 
142.2 
0.048 
0.003 
5 
discal cell 
427.2 
63.2 
0.234 
0.031 
4 
C. ce sonia 
sex brand 
411.3 
40.5 
0.231 
0.012 
3 
discal cell 
216.3 
21.1 
0.216 
0.016 
3 
changes in the basic structure of the sex brands. Still, there are some 
striking differences in their fine structure for which there is no ready 
explanation. These differences include: 1) placement of sex brand 
(forewing vs. hindwing), 2) scale density (some species have sex 
brands in which there is no apparent increase in sex scale density 
compared to surrounding areas), 3) presence or absence of scales in 
the sex brand, and 4) changes in color with male age or death. The 
biological rationale for these differences will have to await more 
detailed information on the chemistry and cellular structure of these 
sex brands. 
This study was supported by funds from NSF Grant BNS 
78-11211 and an Arizona State University Faculty Grant-in-Aid, 
both to R. L. Rutowski. We thank Dr. D. J. Pinkava for identifica- 
tion of plant specimens and Mr. L. Marshall for helpful comments 
on the manuscript. 
Table 4. The relationship between sex brand color and wing condition in 
E. nicippe. 
Sex brand color (no. of males) 
Wing 
Condition 
Orange 
Half orange, 
Half white 
White 
Fresh 
6 
14 
3 
Worn 
0 
3 
9 
Very worn 
0 
0 
X 2 = 20.8, p < 0.0005 
5 
