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OF THE 
BROOKLYN ENTOMOLOGICAL SOCIETY 
VoL. X1V APRIL, 1919 No. 2 
oe 
REMARKS ON THE ORIGIN AND SIGNIFICANCE OF 
METAMORPHOSIS AMONG INSECTS.* 
By G._C. Crampton, Ph.D. 
In attempting to trace the lines of development of the higher 
insects, the question of the origin of metamorphosis and of its 
value as an index of relationships among the higher forms has 
naturally arisen; and, while I do not think the presence or ab- 
sence of metamorphosis can be taken as the important factor in 
determining the relationships of the insects under consideration 
(as is true of the comparative morphology of recent and fossil 
adult insects, or of immature forms), this feature cannot be 
wholly ignored in such a study. That the occurrence of meta- 
morphosis cannot be taken as the deciding factor is evidenced 
by the fact that it may occur in the males, but not in the females 
of the same species of Coccidze and other Homoptera, so that 
when its evidence is not in accord with that of comparative mor- 
phology, and other features, one cannot help but feel skeptical 
as to its value unless the evidence it offers is .confirmed from 
other sources. 
A study of the higher forms, and the types from which they 
were probably descended, has convinced me that an ancestral 
group may include some representatives which have developed 
the tendency toward undergoing a metamorphosis, to a marked 
degree, while other representatives of the same ancestral group 
do not exhibit any marked indications of such a tendency. Sim- 
ilarly, in two extremely closely related groups derived from such 
a common stem containing some members which exhibit a 
* Contribution from the Entomological Laboratory of the Massachusetts 
Agricultural College, Amherst, Mass. 
BULLETI N 7 al MusewS/ 
