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Fig. 4. 
Saturnia pavonia-major.—A specialised wing, vein VIII of secondaries absorbed, 
veins IV 1 and IV 2 ona long stem, furcate, the piece between IV 2 and 
IV 1 still remaining angulate, and morphologically belonging to the cross- 
vein. Compare with figure of Attacus (ante, p. 47), where, under a further 
advance in specialisation, this piece has become absorbed, rounded, and 
represents base of IV 2. As compared with Hemileuca, vein III 1 + 2 has 
progressed from above cell to nearly tip of wing, and is absorbed by III 3+4 
—a clear and expected specialisation. The cross-vein is long between IV 2 
and IV 3, and shows signs of breaking in the middle, which it finally does 
in Attacus. It is thus seen that fundamentally the wings of Saturnia and 
Hemileuca agree in pattern and modus of evolutionary development. The 
slightly shorter stem of IV 1 and IV 2 in Hemileuca precedes the longer 
stem of Saturnia. It is quite impossible that this stem, in both cases 
prophetic of Azttacus, could be related to the stemless separate upper 
median branches of Automeris and Aglia. 
