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Psyche 
[June 
bacterial septicemia, despite stringent sanitation and daily replace- 
ment of the host plant. Ultimately 16 pupae were obtained, but 9 
of these died without showing development. The remaining 7 pu- 
pae proceeded rapidly to the pharate adult, but failed to eclose. 
On February 15 they were all dissected to determine the pheno- 
types of the pharate adults — an easy and reliable procedure. Ex- 
amples of the early stages were preserved and the life-history will 
be described elsewhere. 
Results and Conclusions 
All of the pharate adults (5 males, 2 females) were in good 
enough condition for the ventral hindwing phenotype to be deter- 
mined (one female had to be degreased). All were completely 
normal, with the dark ventral pattern precisely as it occurs on 
wild specimens from the mountains. 
Despite the small sample size, the use of the candle, and the 
overall logistical difficulty of the experiment, this is a definitive 
result since the phenotypes were so consistent and because no 
known Nearctic Pierine reared under the same conditions would 
have given the same result. Obviously we cannot exclude the pos- 
sibility of a latent polyphenism, but it is made much less probable 
by the demonstration that it cannot be exposed under the most 
effective rearing regime known for that purpose. Since no Nearctic 
species yet tested has so canalized its phenotype, the likelihood that 
R. santamarta is a close relative of the species it most resembles is 
diminished. 
Why lose the potential for polyphenism? There is no obvious 
selective advantage in doing so. In Holarctic populations it is 
merely submerged when selection for an appropriate phenology 
alters photoperiodic thresholds. This is especially easy in taxa in 
which phenotype is somehow coupled to pupal diapause, since all 
diapaused pupae will yield dark adults. We do not know if R. 
santamarta is capable of diapause; certainly it would make sense 
during the wettest months (October and November), but we do not 
know what the environmental cues might be. At any rate, the 
animals collected in January 1977 were in very mixed condition, 
suggesting overlapping broods during the “verano.” As noted be- 
fore no sign of seasonal phenotypes has been detected even though 
