1972] 
Young — Dismorphia virgo 
177 
tative and qualitative differences in secondary compounds between 
young and old parts of plants. This question is raised here in a 
speculative manner since the primary selective advantage of laying 
eggs on young leaves (when available), which is known to occur in 
many species of butterflies, may have other ecological consequences 
bearing on the problem of labelling a species as “palatable” or “un- 
palatable”. 
Summary 
( 1 ) The life cycle, larval host plant, and developmental time of 
D is morphia virgo are reported for the first time. 
(2) Breeding populations of the butterfly exploit the same larval 
host plant, Inga pittieri (Leguminoseae) , at two different mountain 
localities in central Costa Rica, 
(3) The developmental time of D. virgo on old leaves of the host 
plant is about 73 days, while on young leaves it is about 45 days, a 
significant reduction in this ecological statistic. 
(4) There is selection for oviposition on young leaves when these 
become available in a habitat. The availability of young leaves in a 
given habitat is probably dependent upon local edaphic and ecological 
factors and may vary considerably among different geographic re- 
gions. Such oviposition-site selectivity may be selected for in popu- 
lations of palatable butterflies since it results in a reduced risk of 
predation or parasitism since the insect spends less time as a larva. 
But since many tropical plants have seasonal vegetative growth pat- 
terns which vary within species in different habitats, it is hypothe- 
sized that any observable changes in predation or parasitism rates in 
the herbivore population are partly accountable in terms of these 
patterns. 
(5) The regular co-occurrence (at least for July and August) of 
adult D. virgo with other butterflies which resemble the female to 
some degree suggests the possibility of the existence of a mimicry 
complex at each locality studied. The butterfly may be a Batesian 
mimic of the ithomiid, Oleria zelica pagasa which occurs at each lo- 
cality; D. virgo is less abundant than O. zelica pagasa at each lo- 
cality. The presumed palatability of D. virgo is suggested by its lar- 
val host plant, the cryptic appearance and behavior of the larvae, and 
the very low population density. At one locality, Cuesta Angel, a 
third butterfly, the pierid Itaballia caesia tenuicornis , may also enter 
the mimicry complex, although it bears less mimetic resemblance to 
the other two butterflies. It is very abundant during July and Au- 
