BIOLOGY OF SATURNIID MOTHS—BLEST ANS) 
but not all, of the species are equipped with poisonous abdominal 
hairs. The species which independent characters indicate to be the 
most primitive possess extremely tiny vestigial eyespots. In Hylesia 
nanus, at least, these are not exhibited during the display, for the 
wings are so strongly elevated that their dorsal surfaces touch over 
the insect’s back. Here, however, there is no abdominal curling 
component. In the vast majority of Zylesia the eyespots have been 
eliminated altogether, the abdominal curling components are exag- 
gerated to the point at which the terminalia are approximated to 
the ventral surface of the thorax in display, and the insects are 
definitely distasteful, for they are rejected by marmosets and coatis. 
Throughout these displays the antennae, which are small, are kept 
retracted against the sides of the thorax, where they are concealed 
among the concolorous thoracic hair. The final episode of evolu- 
tionary history, in which the antennae are incorporated into the 
displays, again necessitates a jump to a further group of genera, 
that containing Dirphia and its allies. 
These moths do not possess poisonous hairs, but they are malodor- 
ous, and in palatability tests with marmosets and coatis, unequivocally 
distasteful. They are also tough. While few Automeris will with- 
stand a bite from a marmoset without suffering disablement, the 
moths in the present group will withstand a great deal of interfer- 
ence without distress. Primitively, the antennae are small and not 
exhibited during display (e.g., Molippa simillima, MW. latemedia, 
Dirphia (Dirphiopsis) ewmedide, D. (D.) agis). In Dirphia (Dir- 
phia) avia, they are protracted throughout display, and are relatively 
larger. In D. (Periphoba) spp. they are very much larger, bright 
lemon yellow, and clearly serve as an aposematic signal in themselves. 
Finally, in this group, as we have seen, the degree of distastefulness 
has apparently reached a point at which over-all aposematic coloration 
independent of display has become a possibility, and sustained 
displays are no longer performed. The whole series is summarized in 
plates 2-5. 
Thus all the hypothetical stages in a long series of evolutionary 
change have been found to be present in contemporary species, so 
neatly dovetailed that we can have confidence in their validity. 
While they may be extended to include the various other types of 
protective coloration, to do so would require a discussion of some of 
the other saturniid subfamilies in which the best evidence is to be 
found, and for this there is no space in this article. 
Now the mode of protective coloration should have one important 
potential evolutionary consequence which has hitherto been over- 
looked: the modification of lifespan. Once the individual insect’s 
reproductive life is over, its further fate as an individual might be 
supposed to exert no influence upon the survival and reproductive 
