Studies in the Theory of Descent, Volume I

by August Weismann

VII.

Phyletic Development of the Markings of the Sphingidæ. Summary and Conclusion, p. [370].

The oldest Sphingidæ were devoid of marking, [370]. Longitudinal stripes the oldest form of marking, [371]. Oblique striping, [373]. Spot markings, [375]. The first and second elements of marking are mutually exclusive, but not the first and third, or the second and third, [377]. Results with reference to the origin of markings; picture of their origin and gradual complication, [380]. General results; rejection of a phyletic vital force, [389].

II.

ON PHYLETIC PARALLELISM IN METAMORPHIC SPECIES.

Introduction, p. [390].

I.

Larva and Imago vary in Structure independently of each other, p. [401].

Dimorphism of one stage only, [402]. Independent variability of the stages (heterochronic variability), [403]. Constancy and variability are not inherent properties of certain forms of marking, [407]. Heterochronic variability is not explained by assuming a phyletic vital force, [410]. Rarity of greater variability in pupæ. Greater variability more common among caterpillars than among the imagines. Causes of this phenomenon, [412]. Apparent independent variability of the single larval stages. Waves of variability, [416]. Saturnia Carpini an instance of secondary variability, [419]. Causes of the exact correlation between the larval stages and its absence between the larva and imago, [429].

II.