344 
Psyche 
[December 
None of these authors made reference to the snake-like appearance 
of the pupa. The resemblance may not be so obvious in green pupae. 
Ontogenetic variability 
With respect to the number of instars of Dynastor darius, the 
situation may be similar to that of Manduca sexta (Sphingidae). The 
larvae of M. sexta initiate the sequence of events leading to pupation 
at a critical weight, independent of the rate of growth (Nijhout and 
Williams, 1974a, 1974b). Like Manduca, Dynastor exhibits variabil- 
ity in the number of larval instars, corresponding with variability in 
growth rate, and it appears that the larvae commit themselves to 
pupation when a critical size is reached. In contrast to Manduca 
however, commitment in Dynastor may take place during the next to 
last instar, as evidenced by the fact that the final instar always has a 
head capsule pattern different from that of previous instars. Another 
possibility is that there may be two commitments: one to the final 
head capsule pattern, and another to pupation. 
Preserved material (head capsules, pupal skins, adults, and larvae 
in alcohol) of Dynastor darius, upon which this study was based, 
labeled as Lots 78-75 (an individual collected as a pupa) and 78-84 
(reared from eggs), has been deposited in the Museum of Compara- 
tive Zoology, Harvard University. 
We would like to thank the Smithsonian Tropical Research 
Institute, Panama, for use of their facilities, Mr. Gary Stump for 
locating a wild pupa of Dynastor darius on BCI, Mr. Nigel Franks for 
assisting with rearing, Mr. Gordon B. Small for identification of the 
butterfly, and Mr. Norman Woodley for reading the manuscript. 
References 
Blandin, P. 
1976. La distribution des Brassolinae (Lepidoptera-Satyridae). Faits et prob- 
lemes. pp. 161-218. In H. Decimon, ed., Biogeographie et Evolution en 
Amerique Tropicale, Publ. Lab. Zool. de l’Ecole Normale Superieure 
No. 9. 
Blandin, P. and Descimon, H. 
1977. Contribution a la connaissance des Lepidopteres de Fequateur. Nouvelles 
donnees sur les Brassolinae [Nymphalidae] de l’occidente. Annls. Soc. 
ent. Fr„ (N.S.) 13: 75-88. 
Burmeister, H. 
1873. De Morphonides Bresiliens. Rev. Mag. Zool. Pureet Appl., (3)1: 17-47. 
