This data concerns the development of a defoliating
moth widespread in western North America
(i.e., north of Mexico).
According to Boersch-Supan (2021),
the insect passes hrough successive stages
\(j=1,\ldots,r\), delimited by \(r-1\) moults.
The data was originally used in a 1986 publication
but has been corrected for two sampling occasions;
the data appears in Candy (1990) and
was analyzed in Boersch-Supan (2021).
See the latter for more references.