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Psyche 
[December 
uals in a group derived from a single cluster of eggs. From these 
preliminary observations, it seems that different genera of ithomiines 
possess very different strategies of oviposition and subsequent larval 
behavior. With further field studies on these and other Costa Rican 
species within selected genera, it will be possible to examine these 
adaptations in terms of phylogenetic affinities within the Ithomiinae. 
Other field studies will emphasize the correlation of ecological prop- 
erties of habitat and how these influence the type of oviposition and 
clustering of larvae. 
Defensive Behavior of Larvae 
Earlier larval instars of H. nero are relatively more cryptic in ap- 
pearance than the fifth instar and do not build solitary nests. Final 
instar larvae build solitary nests (Fig. 2-D) and are more brightly 
colored than earlier instars. These behavioral and morphological 
differences among instars suggest differences in palatability of larvae 
as a function of their age. The nest-building behavior of solitary 
final instar larvae may be an adaptation against invertebrate (ants, 
predatory hemipterans, spiders, whip scorpions, etc.) and small ver- 
tebrate (lizards and frogs) predators that forage in understory herb- 
age. The increased conspicuousness in coloration of the final instar 
suggests increased unpalatability while the nesting behavior indicates 
reduced unpalatability. This resulting level of intermediate un- 
palatability may be carried over from the final instar to the adult, as 
indicated in the latter by the crypsis of wing transparency. 
It is likely that species of Hymenitis such as nero are generally 
only intermediate in unpalatability as compared to various orange- 
wing genera such as Mechanitis and Godyris which are probably very 
unpalatable. The more pronounced unpalatability of these latter 
genera is suggested by ( I ) brighter coloration of larvae and adults, 
(2) various types of cluster oviposition patterns, and (3) various 
levels of larval gregariousness, ranging from loose (i.e., Godyris) to 
highly coordinated (i.e., Mechanitis) behavior among individuals. 
But since it is known that many unpalatable tropical butterflies, 
most notably in the Heliconiinae, have single oviposition and solitary 
larvae (Alexander, 1961), it is essential to determine the relative 
palatability of species among these ithomiine genera before making 
such correlations. Many other selection pressures not related directly 
to the development and expression of unpalatability may account for 
the evolution of cluster oviposition and larval gregariousness. 
Summary 
( 1 ) The life cycle, developmental time, and larval host plant 
